Episode Name: The Greater Good (a.k.a. Sides)
Episode Overview: After another funeral, tempers rise as the survivors' suspicions of each other grow, and an unlikely survivor vows revenge. The events that landed Sayid on Flight 815 play out as he engages Locke in a psychological game of cat and mouse to uncover the truth about the mishap that claimed Boone's life.
Episode Number: 21
Episode Season: 1
Episode First Aired: 2005-05-04