I must warn you that there are SPOILERS ahead for the entirety of NML. If you DON'T want the story ruined, then I would break off in December.
--Circa July 6, night: Batman tells Oracle (a week after the fight with Cain) to call in and forge his outside allies (Robin, Nightwing, Azrael, Oracle, and Batgirl) into the Batsquad--it has taken the better part of six months, but he realizes he can't win by himself [Detective Comics #734], Batman makes contact with Nightwing and informs him to meet Robin and find a way to enter NML--Oracle sends Robin plans on how to enter NML (Robin remarks that NML began over 6 months ago) [Nightwing #34; Robin #67]--Batman give them 24 hours to enter NML--he goes to confront Gordon and Gordon punches him--before he leaves in shame Batman tells Gordon that Two-Face isn't an ally he can trust [Legends of the Dark Knight #120].
--Circa July 7: Nightwing and Robin maneuver through the sewers and tunnels beneath Gotham--before they start for street level, they must defeat the "combined" forces of Tommy Mangles and Gearhead [Robin #67], Oracle, at Batman's request, finds a way to send out an inside NML cable TV broadcast to the nation [Batman Chronicles #17].
--Circa July 8, early evening: the Bat-squad convenes: Azrael, Oracle, Nightwing, Robin, and the mysterious nameless girl--Batman arrives--Batman and Nightwing confront Batgirl who is revealed to be Huntress--Batman kicks Huntress out of the Batgirl costume (knowing that she will go rogue) [Legends of the Dark Knight #120].
--Evening: the nameless daughter of Cain becomes the new Batgirl, Batman gives tasks to all of his squad in order to take back NML--they leave--there's work to be done [Legends of the Dark Knight #120].
--Late evening: Huntress, no longer Batgirl, fights thugs while conversing with Superman. The rest of the JLA comes to Gotham to fight the Locus. [JLA #32]
--Night: Batman accompanies Nightwing to the shore, and gives him information on Blackgate. Batman returns with Robin to Oracle's HQ, and Nightwing begins to prepare to enter Blackgate.
Oracle and, later, Penguin, fill Batman in on the happenings in Robinson Park. Billy Petit, Foley, and a splinter group of cops confront the core GCPD and leave Tricorner to form a rogue team whose diplomacy is based on the gun. Batman and Robin enter Robinson Park to locate some disks (what's on those disks?) Batman needs in order to save Gotham--instead, they find Poison Ivy trapped by Clayface (who's been supplying fruit to Penguin in exchange for cash) [Shadow of the Bat #88]
Nightwing's mission: re-take control of Blackgate before Lock-Up (Lyle Bolton) and KGBeast become too entrenched and too powerful (before Lock-Up realizes he has an army)--Nightwing infiltrates Blackgate but runs into the Trigger Twins and KGBeast and is shocked unconscious by Lock-Up [Nightwing #35], hallucinates a conversation with Jason Todd [Nightwing Secret Files and Origins #1], and is tossed into "the hole" with the rest of Blackgate's hard-liners that Batman has already taken down (Scarecrow, Scarface, Tumult, Steeljacket, Firefly, Monsoon, Mad Hatter, Black Mask, Dynamiter, etc.) [Nightwing #36]
Azrael's mission: team up with Batgirl to take down Scratch--Batman confronts Azrael in Leslie Thompkins' MASH sector wondering why he hasn't moved on his mission--Scratch seems to be making some kind of move--Batgirl accompanies Azrael to the meeting place, but Azrael is discovered and attacked by Scratch [Azrael #56].
--10 PM: Leslie Thompkins finds herself overwhelmed in the MASH sector she (with help by former Black Masker Mikey) works in--and no wonder: she has an injured Mr. Zsasz tied up, Killer Croc (wanting to kill Zsasz) wandering around outside her perimeter, Petit and Huntress and the Strong Men (wanting to kill Croc) needing medical attention, and Batman and Batgirl bringing in medical supplies--everything breaks down as the rain begins to fall--it culminates with Batgirl and Huntress fighting each other to save Leslie from Zsasz, Petit and Croc fighting to get at Zsasz, and Leslie trying to talk Zsasz out of killing her--Killer Croc ends up saving Leslie's life and Batman returns with a concrete tube to contain Zsasz, but Killer Croc escapes into the sewers--Batman carts Zsasz off to Blackgate (which he says Nightwing will have control of in 26 hours) and Leslie makes a deal to place peace in Batman's heart [Batman Chronicles #18], Robin's mission: locate a hidden cache of food and supplies within NML (this takes place before Lock-Up is taken down) [Robin #68].
--July 9, pre-dawn: Batman awaits Clayfaces return (to "get some mud" on his boots), Huntress agrees teams with the Petit and become a soldier in the Strong Men (Petit's gang)--Batman and Robin free Poison Ivy after Clayface returns [Batman #568]--Poison Ivy grows a new "suit" of Ivy and proceeds to "kill" Clayface by entrapping him in a green mound [Detective Comics #735], Nightwing finds himself caught in between a battle of Blackgate's "the hole" inmates--some want him dead, other want to keep him alive--Ventriloquist convinces the fighting inmates to a truce--Nightwing comes up with a plan to blow a hole in their cell using hundred year old gunpowder residue [Nightwing #36], Batgirl steals Scratch's army's guns [Azrael #57].
--Dawn: Nightwing and the inmates are forced to blow a hole in the wall when Lock-Up decides to drown the inmates--Nightwing has to fight through the inmates, the KGBeast, the Trigger Twins and Lock-Up [Nightwing #37], Azrael (and Batgirl) defeat and humble Scratch in front of his mob--they dissipate, Azrael finds some medical supplies to take back to Leslie, and Scratch slinks off to lick his wounds [Azrael #57].
--Day: Gordon sends Montoya to break off his truce with Two-Face, an unknown outside interest has a mysterious female (Mercy) track down (in Columbia) and hire Bane away from the cartels to re-enter NML (but why??) [Detective Comics #735], Bock leads in some of Batman's troops to clean up after Nightwing captured all the prisoners [Nightwing #37].
--Evening: Two-Face (who is virtually untouchable) kidnaps Montoya and her entire family and threatens Gordon--Batman (after finding the disks destroyed) agrees to let Ivy stay in Robinson Park in exchange for regular fruit deliveries in to NML--Batman and Oracle figure out a way to trick Catwoman to steal some back-up copies of the disks existing in New York City, Catwoman hears about a priceless green cat head gem on display ripe for the plucking [Detective Comics #735].
--Close to 1 AM: battered and near exhaustion, Nightwing stumbles into Oracle's apartment and collapses [Nightwing #37].
--Circa July 10 or so: investigating the resurgence of power in Chinatown, Batman stumbles onto a plot by Mr. Freeze to destroy NML's infrastructure--after a long drawn-out battle (complete with much witty repartee incorporating big multi-syllable words like "hubris" and "bailiwicks" and literary/mythological allusions to Prometheus, the Iliad, and the novel Frankenstein) Batman wins by blowing up the only working power plant in NML (why?)--but remembers to tie up Freeze's goons loosely so they could conveniently escape--Freeze ends up floating away (like the Frankenstein monster who he quotes) and escaping on an ice chunk [Legends of the Dark Knight #121].
--Circa July 11, night: Nightwing, under Oracle's care, wakes up to find his fever down, Petit and his Strong Men decide to take Oracle's watchtower, thinking that by taking down the GCPD's brains, the rest will fall, meanwhile, as the assault secretly begins, Nightwing and Oracle discuss their relationship, they kiss--then Petit and his boys storm the front door and Huntress bursts in through the roof [Nightwing #38], Oracle pulls a neat trick by blinding the invaders, giving her and Nightwing enough time to escape into her safe room, Oracle then unloads on Huntress, Petit, and the rest of the Strongmen trapped in her home—Petit goes berserk, firing at will with his machine gun—having enough, Huntress rebels, helping Oracle and Nightwing escape through an abandoned elevator passage—Nightwing leaves with Oracle to continue recovering, even though Huntress rebelled, she will return to the Strongmen, and Oracle works to rewire her cyberspace [Nightwing #39].
--Circa July 15 or so: a few days of investigation (but days after Mr. Freeze escapes Batman) finds Robin locating a myth about a cache in the sewers--so into the sewers he goes--he finds the cache, but also that Ratcatcher and his rats have control of it (with the intention of world domination by rats or something goofy like that)--Robin is attacked by the rats [Robin #68], but he manages to escape by shocking the rats and diving into raw sewage--he pulls himself from the sewage but falls into a fever-induced stupor, a group of abandoned teens calling themselves "the Wolflings" find him and decide to go look for the food cache themselves while Robin recuperates, Mr. Freeze runs into and freezes Tommy Mangles and Gearhead [Robin #69] and then encounters Ratcatcher (who is still chasing Robin)--the Wolflings stumble onto the food cache (all but their leader "Aragoth" retreats)--it's up to a feverish Robin to take down Mr. Freeze and Ratcatcher and call in Lt. Bock to carry the supplies and the captured Supervillians topside--in the end, Batman carries an exhausted Robin home with him to get him stabilized [Robin #70].
--Circa July 17: the green cat head gem Catwoman was going to steal in Manhattan turns out to be a prearranged recording by Oracle asking Catwoman to meet Batman in the ruins of Gotham City--completely pissed off, Catwoman decides to steal her way into Gotham [Catwoman #72].
--Circa July 18, dawn: Catwoman sneaks into NML, eluding Navy SEALs and the Coast Guard and rendevours with Batman--Batman asks her to steal the disks for him and break into NML with them--then he seals the bargain with a kiss--Catwoman tries to sneak out of NML through a service tunnel but it becomes flooded when men hired by the mysterious woman named Mercy (working for the Outside Interest) accidentally blow it up [Catwoman #72]--Catwoman works with the men to open the end of the tunnel and help them escape, then she annexes them and makes them work for her (which they don't mind doing seeing how she's hot) [Catwoman #73].
--Circa July 19: Catwoman's mission in Manhattan: break through an elaborate private security force hired by Bruce Wayne of ex-Marine psi-ops called "Hardcases, INC" to steal the disks--using a devious plan, Catwoman combines a diversionary frontal attack with her hiding inside their building (after entering as Selina Kyle) to take the disks and elude its protectors [Catwoman #73], afterwards, she double crosses Batman by offering the disks to the highest offer on the internet [Catwoman #74].
--Circa July 20: The Outside Interest tells Mercy that he wants those disks--she should use any means necessary to capture them--in the meantime, Maxie Zeus also expresses interest in buying the disks [Catwoman #74].
--About midnight: Hard Cases, INC shows up as the "deal" is about to be made--they get into a fire fight with Maxie Zeus' men while Catwoman makes the real exchange with Mercy--Mercy double crosses her and gets ready to execute her, but Hard Cases show up to take back the disks--Mercy shoots Catwoman in the hip, who then keels over into the river--Mercy, having disposed of the Hard Cases, drives off and reports on her cell phone to the Outside Interest that she has the disks, but that Catwoman escaped [Catwoman #74], Catwoman remembers back to when she was a child (how she was trained in the circus—what is it with Batman characters and circuses?)—how her past friend, before he died, taught her "never to let them see you hurt"—Catwoman crawls out of the river and into a sexy negligee where she patches herself up [Catwoman #75].
--July 22: Catwoman breaks onto a military base and kidnaps a helicopter pilot long enough for him to fly her into NML [Catwoman #75], Azrael defends Catwoman from the last remnant of Hardcases, INC (Stone) who followed her long enough for her to crashland into NML and give the valuable disks to Batman [Azrael #59], later Catwoman collapses with fever—a mysterious figure steps from the shadows… [Catwoman #75].
--Late July: Batman is summoned by a make-shift Bat-signal to find the kidnapped "King of Gotham" an urban legend who actually exists--Batman must defeat Killer Croc (who's intent on using the King for his own gains) to rescue him--but even he is amazed that the King turns out to be a career two-bit criminal who's turned over a new leaf [Shadow of the Bat #89]!
--Circa July 23: Robin is still weak from his ordeal in the sewers (two weeks after "Assembly"), meanwhile Killer Croc is rampaging, taking over neighborhood after neighborhood in an effort to become a "serious" gangster and player in NML, Tim discusses with a very spry Nightwing (still hanging out with Oracle) about what explanation he is supposed to give to his father for running away again—Robin and Alfred discover that Croc is making a move on South Grand towards Penguin's territory, but Robin is knocked unconscious, Croc comes into conflict with Penguin a bunch of GCPD's guns and Robin is tied to his front bumper (PS—there is absolutely no way that Montoya has been rescued by this point as Robin and Nightwing are both recovering, so, in order for the story to work, you have to pretend she isn't there and her character is that other Latino cop Rucka created in "Mosaic") [Robin #71]. Alfred helps Robin escape and stop Croc from tearing Penguin's forces a new asshole.
--Circa July 24: Tim calls his dad and explains that his excuse for being trapped in NML was a high school dare—Tim's father raises cain with the state legislatures in an effort to turn public opinion against the NML tragedy [Robin #72]
--Circa July 26: Selina Kyle wakes up in Penguin's lair (naked, thankfully) a few days after she was found by one of his men—Penguin reveals who the Outside Interest's identity is and asks her to steal everything of his "that isn't nailed down" in order to stop the Outside Interest's assault on Gotham—now, in order for this story to work, Catwoman must take a few months "hiatus" to plan—her entire "capture the disks" adventure lasted about 72 hours and to suddenly place her in the events unfolding post "Assembly Redux" would require a time machine [Catwoman #76].
--Towards the end of July: Tim's dad has raised enough hell for Tim to be on every channel—the public appears to be changing its opinion towards NML [Robin #72, NML Secret Files & Origins #1].
--Circa July 30 (we know it's three months before Halloween), 11:45 PM: Batgirl's mission--infiltrate a war zone, locate and defend a gas station which may have some of the last remaining gasoline in Gotham (in order to help Leslie's MASH unit generators stay running)--she takes it and waits for Batman to arrive [Batman #569].
--Circa July 31, 12:15 AM: Batman and Nightwing (probably after the Blackgate story) can't risk helping her out--they decide to wait until dawn--it is a test for Batgirl, a test which Batman feels she is fully capable of handling [Batman #569].
--Pre-dawn, 3:45-4:15 AM: some punks (which Batgirl previously defeated) have a rocket launcher and want to prove a point--Batgirl takes the mooks down, but not before the rocket launcher goes off and the station is destroyed--Batgirl chases away the gang, when Batman arrives around 4:30 AM, the owner of the now defunct station gives Batgirl some of his stash--enough to keep the generator going [Batman #569].
--Circa the first week in August: in a marvel of visionary storytelling (with the return of the word "balliwick"), Bane breaks into Gotham City--after using a car and a ramp to launch himself into NML, he blows up the car--Batman, conveniently nearby, hears the explosion and, ignoring the dead and dying innocent civilians lying on the ground, gives chase through the niter phosphorescing of the slime and engages in a battle royale (and, of course, snappy dialogue) with the "loser mook" in an abandoned prop warehouse--Bane escapes in the end after planting a divisiary bomb beneath a soup kitchen [Detective Comics #736].
--Early August: Batman runs into the Joker and meets Harley Quinn for the first time--she distracts him long enough for the Joker to escape [Harley Quinn].
--The next day: Joker, tired of Harley (or maybe confused about his feelings towards her) tricks her into a rocket and decides to blast her into the atmosphere--after lift-off, she defuses the rocket and crashes it into Robinson Park [Harley Quinn].
--Circa August 10-11: a month after his explosive confrontation with Mr. Freeze, Batman again notices lights in Chinatown--investigating, he runs into and teams with Lynx to put an end to the Fists of Heavenly Serendipity, a gang who has enslaved humans to produce kilowatt energy--Batman stands by and watches as a child is beaten up (because there are too many bad guys), Lynx uses the word "hubris" twice in a sentence, her origin and King Snake's name is screwed up, and then, when surrounded by the enemy, Batman and Lynx are forced to pop open a can of butt kick (and snappy repartee) [Legends of the Dark Knight #122] on Jade-Faced Wu and his men--Batman drags a wounded Lynx away from the battle to a groovy herbalist to save her life (dig?)--when they return to finish what was started, the find that the slaves have revolted, killing Jade-Faced Wu and his men, but one child paid the ultimate sacrifice--meanwhile, elsewhere, Bane plots to destroy the Hall of Records [Shadow of the Bat #90].
--Poison Ivy finds Harley Quinn lying in rubble outside Robinson Park--she nurses her back to health and, after giving her a potion to protect Harley from her poison, finds that Harley has acquired super human strength and agility [Harley Quinn].
--Circa August 15: Harley meets with Batman and agrees to lead him to the Joker's hideout--while Batman busies himself with Joker's henchmen, Harley goes to work on Joker and, when Batman interferes, she knocks him out--Batman wakes up to find that Joker and Harley have made up and, after he escapes from Joker's exploding hide-out, stumbles home to discuss things over with Alfred [Harley Quinn].
--A few days later: Joker and Harley Quinn begin to expand outwards into NML--Harley, while exploring an apartment building in a neighborhood they have annexed, finds a book on dating called "The Code" which she applies into her weird love relationship with the Joker [Batman #570].
--A week later: Harley has settled into a new apartment and is putting the laws of "The Code" to work--and the Joker decides to improve his public image by running for president of NML against Petit [Batman #570], --Circa August 30 or so: Huntress finds out about the election and informs Petit that Joker is paying volunteers and voters in supplies, when Joker learns that no one is likely to vote, he decides to plant explosives around his sector (which Huntress sees and tries to find out what Harley knows)--a lovesick Joker decides to marry Harley Quinn and gets jealous of one of henchmen who is putting the moves on her, so he blows him up--Harley, after escaping the Huntress, decides to abandon "The Code" and the two make up, Huntress watches the bomb go off and, after realizing no one was hurt, leaves Joker's sector [Detective Comics #737].
--Circa September 1: Bock, with the occasional help of Batman and other allies, oversees what he calls "the 100 blocks"--he protects its citizens, teaches them survival and self-defense, and makes sure rival factions can't get a foothold in his territory [Legends of the Dark Knight #123].
--Circa September 2: Bock learns a number of children will die unless they find a rare anti-biotic--he and his veterinarian friend Vanessa must make a deal with Penguin to acquire the needed drugs, afterwards, Joker pays a visit to Penguin and kills one of his prized pepper shrikes [Legends of the Dark Knight #123].
--Circa September 6: the first effects of the Outside Interest are beginning to be seen--cars run on gasoline, electricity works, and Penguin has a working Lexcorp computer, when an accident wounds Bock and kills other member, he finds he must make another deal with the Penguin: fight in a deathmatch with a rival gang member--in exchange, Penguin will use the mysterious Tubman to help the dying children escape NML [Legends of the Dark Knight #123].
--Circa September 7: having trained the entire night with Vanessa's father in Siloh, Bock defeats Angel--defeating Angel spiritually by attacking what he loves most, Penguin uses Tubman to take the kids out of NML, but they are attacked by Angel's gang--Robin assists, but they are pursued into the forgotten train tunnel which will get them out NML--Penguin, recognizing that he is less of an animal (he remembers his encounter with Joker) than most perceive him, helps out--but Angel and Bock fight desperately on the runaway train--they break out of NML, the kids are helped, Angel's militia is arrested for breaking the quarantine, and Bock returns to NML where, by God, he will make his stand [Shadow of the Bat #91].
--The events of Day of Judgment affect NML: Azrael, while trying to rescue Mitzi's mother, finds himself tempted by the spirit of St. Dumas (or was it a hallucination brought on by 4 days without sleep?), but, when offered the opportunity to escape, chooses to stay behind and continue his work with Leslie Thompkins [Azrael #58], Batman leaves NML to assist the JLA in the fight against Asmodel--Robin, Nightwing, and Oracle find themselves facing a gang of long-dead Gotham gangsters zombies [Batman: Day of Judgment #1]. Not too unusual for Gotham, eh?
--Circa September 15: Bane makes his move--kidnapping a girl, he maneuvers his way to a room prepared by the Outside Interest beneath the streets of NML--meanwhile, Batman and Robin notice the effects of the Outside Interest (someone is making things happen in the city), Bane guns players down and blames it on Two-Face--as a result, Two-Face's hold in the Courthouse is attacked by gangs of ticked off factions [Batman #571], Bane makes his way to the Hall of Records--Batman decides to rescue Two-Face before he is killed (Robin cuts him loose before the gangers hang him) instead of stopping Bane who detonates several small, compact nuclear devices beneath the streets of the Hall of Records (in order to push the Outside Interest into the light) [Detective Comics #738].
--Circa September 22: Batman and Batgirl hunt down a man named Shank who supposedly has a way out of NML--disguised as Matches Malone, Batman discovers Flowers' true plan--he steals from and then uses the "escapees" to feed a band of cannibals living in his basement--Batman frees them and takes down Shank's organization [Legends of the Dark Knight #124].
--Circa September 29: Superman returns to NML--he runs into Petit and his Strong Men--Batman comes to protect a couple of citizens, Superman (as Clark Kent) wants to make sure Batman is taking care of himself and also to do something about the dry spell--it's been months since it last rained, probably around when Batman Chronicles #18 took place, Superman creates a rain storm with a little "persuasion" [Shadow of the Bat #92].