Plot summary
After leaving the island, Walt cuts contact with Michael when he admits to murdering Libby and Ana Lucia. A suicidal Michael is approached by Tom Friendly, who explains that the island's power prevents the death of people important to it and convinces him to atone by blowing up the Kahana. Ben calls him once he is aboard and instructs him to make a list of all the people on the boat. In the present, Sayid, furious that Michael is working for Ben, exposes his duplicity to Gault. Ben informs Locke's group that Michael is his spy, and privately warns Alex Rousseau to take refuge in the Temple. She leaves with Karl Martin and Danielle Rousseau, who are killed by Widmore's mercenary squadron, led by Martin Keamy. Alex bargains for her life by revealing herself as Ben's daughter.
Credits
Adapted from Wikipedia contributors, Lost season 4. HTML formatting and reference markers removed.