Justine (Kirsten Dunst) and Michael (Alexander Skarsgård) celebrate their marriage at a sumptuous party in the home of Justine's sister Claire (Charlotte Gainsbourg) and brother-in-law John (Kiefer Sutherland). Despite Claire's best efforts, the wedding is a fiasco with family tensions mounting and relationships fraying. Meanwhile, a planet called Melancholia is heading directly towards Earth threatening the very existence of humankind...