The film's story is based around a newly arrived planet to the solar system, Melancholia, approaching Earth. Some predict it will hit Earth and destroy it, and most believe it will simply pass by our planet. Lars von Trier's film came out of a therapy session where he discussed depression with his therapist who said that typically depressed people act more calmly under extreme circumstances. Thus the narrative explores the different ways in which people act in relation to Melancholia approaching.
Claire's husband John seems to be the voice that states we should not panic as "this will pass". In the end, however, he robs Claire of her pills and overdoses on them. His dismissive attitude towards this impending potential doom reveals that he's secretly overwhelmed and incredibly selfish as he leaves his wife and son to perish on their own. Claire believes the end is near and seems the most out of control. Does this mean she is normally a happy person? And Justine is stoically calm as Melancholia approaches, even to the fiery end of her existence. She represents those with depression as she sleeps with Tim, a co-worker instead of her new husband on their wedding night and is expectant that bad things will happen and thus the world ending isn't that big of a deal.
The film is an exploration of the psyche of human beings when doom is imminent. In fact, the final shot of the film reveals how differently we all respond. Claire shudders, which represents her belief that there is no way out. Claire and her son are seen in a meditative posture which possibly represents their belief that the magic cave they've constructed will protect them.
