"The Variable" is the 14th television episode of the fifth season of Lost, and the 100th episode overall. It originally aired on the American Broadcasting Company (ABC) in the United States on April 29, 2009. The hundredth episode milestone was celebrated by cast and crew on location in Hawaii. In the episode, Daniel Faraday (Jeremy Davies) returns to the island in order to warn its inhabitants of a catastrophe involving the Dharma Initiative research station, The Swan.