This is yet another movie with a theme that the end is near. The entire movie centers on a group of 4 couples meets regularly for brunch, and it could be staged as a play because there is almost nothing that takes place outside of the house the brunch occurs in. Three of the couples have been together years, and one is a new relationship. She is part of the group and he is not. One couple is breaking up and discover that they each have slept with another member of the group. So the dynamics of the group is a bit complicated to begin with.
The disaster is a bomb that releases a deadly gas. First the electricity goes and communication is compromised. No one is to go outside, so they are now stuck under one roof. As the disaster progresses, the news gets worse and the tensions start to rise. The idea gets you thinking about two things. The first and clearest thought is what would you do when the world appears to be at an end, and then secondarily, the end is unknown for each of us. We are all living a mortal life, and are we making choices that reflect that? The movie is light on contemplation (and not as funny as it should be, given that), but it could be food for thought.