"316" is the sixth television episode of the fifth season of ABC's Lost. The eighty-ninth episode of the show overall, "316" aired on February 18, 2009 on ABC in the United States, and was simulcast on A in Canada. The episode was written by showrunners and executive producers Damon Lindelof and Carlton Cuse and directed by Stephen Williams.
The episode begins with Jack Shephard (Matthew Fox), Kate Austen (Evangeline Lilly), and Hugo "Hurley" Reyes (Jorge Garcia) having returned to the island, three years since they left it in "There's No Place Like Home". The narrative then shifts to 46 hours previous where the previous episode, "This Place is Death", left off. Eloise Hawking (Fionnula Flanagan) takes Jack, Desmond Hume (Henry Ian Cusick), Sun-Hwa Kwon (Yunjin Kim) and Ben Linus (Michael Emerson) to a Dharma Initiative station underneath the church called the Lamp Post, which was used by Dharma to find the island; since the island is constantly moving, they developed a way to predict where it would be at a given time. When Eloise mentions that the group only has 36 hours to get on Ajira Airways Flight 316, in order to return to the island, Desmond refuses to join them and leaves. Eloise then tells Jack in private that he must bring something that belonged to his father Christian Shephard (John Terry) with him on the flight and also gives him John Locke's (Terry O'Quinn) suicide note.
The next day, Jack gets a call informing him that his grandfather Ray (Raymond J. Barry) has attempted to escape his nursing home. Jack goes to the nursing home and finds an old pair of Christian's shoes and decides to take them with him. Later, Jack returns to his apartment, where he finds Kate sleeping in his bed. He wakes her and asks where her adoptive son Aaron is, but she refuses to answer. They kiss passionately and fall into bed. The next morning, Jack receives a phone call from a severely beaten Ben, who tells Jack that he must go to a butcher shop and retrieve Locke's dead body. Jack does so, putting Christian's shoes on Locke's feet in the process. He also leaves the suicide note in Locke's pocket.
At the airport, Jack, Kate, Sun, and Hurley all board Flight 316. Hurley was informed by someone other than Ben, and bought all the remaining first class seats on the plane, in order to spare the lives of potential passengers. Sayid Jarrah (Naveen Andrews) also boards the plane, in police custody of Ilana (Zuleikha Robinson). Ben is last to board the plane, which momentarily disquiets Hurley. Also on board is Caesar (Saïd Taghmaoui). During the flight, Jack realizes that Frank Lapidus (Jeff Fahey) is piloting the plane and Frank realizes that they are going back to the island. Jack, who has been given Locke's note by a flight attendant, reads the note, which says, "I wish you had believed me." The plane hits turbulence and there is a flash of white light similar to that caused by the time shifts. The first scene replays, following which, Jack, Kate and Hurley are found by Jin-Soo Kwon (Daniel Dae Kim), who is driving a Dharma van and wearing a Dharma jumpsuit.
This episode and "The Life and Death of Jeremy Bentham" were written at the same time by executive producers Lindelof and Cuse. "The Life and Death of Jeremy Bentham" was originally meant to be aired first, but the order was switched because they felt it made more sense and was "cooler" and "there is probably some good information to get in “316” before."