Disturbing look at humanity Spoilers ahead!
Starts off with a bang, literally, as bombs are hitting NYC and tenants scramble down steps futilely looking for safety. Eight do manage to force their way into the super's, Mickie, homemade bomb shelter. The survivors are Eva and her French boyfriend, Sam, brothers Josh and Adrien, Josh's friend Bobby, Marilyn and her daughter Wendi, and Devlin. Considering the situation things are pretty civilized despite the food shortage, cramped quarters and the different personalities.
They are found by some unknown military/scientific group after they disclosed their location on a walkie talkie type device. Wendi is taken, and the other survivors kill the three military types that stay in the shelter. With Marilyn going crazy due to grief Josh agrees to don a suit one of the military guys was wearing and go look for Wendi. He takes one of the two weapons they scavenged and goes outside.
Tunnels from doorway to doorway created ostensibly to provide protection from radiation lead Josh right to where Wendi was taken. He finds a main area with children being held in some kind of coma like state, but gets discovered and has to fight his way back to the shelter abandoning his weapon as he goes. The military then welds their door shut from the outside effectively trapping them inside. No idea what is going on, but if things are so bad they need to preserve children for when the environment settles down why are they searching in one of the places that got bombed? Why is a well equipped group in the city in the first place, why do they seemingly ignore three of their number getting killed, and then set up a tunnel to lead the people that just killed them right back to their main camp?
It's at this point things take a turn for the worse. Devlin is killed while confronting McKie over a hidden food stash. Marilyn's mental state deteriorates, Josh starts showing signs of radiation poisoning, his friend Bobby starts acting more bizarre, Sam gets more ineffectual and lost as the protections of civilization are now completely gone, and Mckie gets tied up and tortured to reveal his food source.
Josh and Bobby start abusing Marilyn who appears to go along with it initially and, after her one attempt to seek help from Eva and Sam fails, she quickly deteriorates mentally culminating in her casually being killed by the duo who merely state, "she just broke." Eva turns to Adrien for companionship as Sam's inability to cope with what is going on renders him useless. I'm glossing over the depravity that takes place, but suffice it to say Josh and Bobby take control of group and reveal the worst people have to offer.
Eva enlists a mostly broken Sam in a scheme to get a gun Mckie told her about. While he's successful getting the gun, in the confrontation that follow he's not mentally strong enough to control the situation. As Josh and Bobby, who for a while now look like they belong in a Mad Max movie, try to get the gun from Sam, Eva tells him to give it to Adrien. Sam, probably jealous of the more competent Adrien, shoot him instead. Josh starts beating Sam while Bobby picks up the gun and in a curious twist appears to point it at the back of Josh's head, but before he does anything Eva slits his throat with the lid of a can. Had their depravity finally sunk in to Bobby? or was he realizing that siding with Josh would eventually lead to his own demise? We'll never know, but interesting development to throw in that late.
Josh is shot, but before dying sets the shelter, and himself, on fire. While Mckie and Sam try to put out the fire, Eva dons the one remaining military suit, grabs some supplies and escapes through the sewer leaving Mckie and Sam to certain death. As the shelter burns Mckie takes a glance of a photo of him and presumably his wife in a long ago time, and Sam appears content knowing Eva was trying to get to safety.
Unfortunately Eva finds a city devoid of any signs of life, no signs of the military presence and what looks like debris is still falling from the sky. The camera pans around with Eva representing a spark of life appearing completely out of place in the desolate landscape, her bag of meager supplies hanging inadequately at her side. I'm pretty sure their is life somewhere, but it certainly doesnt appear Eva will be able to find it given her surroundings.
A disturbing, but perhaps accurate, look at what would happen if civilization breaks down.