S3E5 · The Cost of Living

Complete story — includes the ending

After Yemi's death, Eko takes over his church and learns that guerillas are stealing the town's vaccines. Eko plans to sell the vaccines first and is attacked, but kills the men inside the church. The villagers close it down and Eko is advised to repent. In the present, Juliet asks Jack to operate on Ben and "accidentally" let him die. Locke leads a group to the Pearl and they encounter a delirious Eko, who does not join them in the station when he cannot find Yemi's body in the Beechcraft. The group turns on other cameras, finding one station run by a one-eyed man who turns his camera off. A vision of Yemi tells Eko to confess his sins, who insists that his actions were always to survive and protect those he loved. Yemi denies being his real brother and walks off, and Eko follows him and is attacked by the smoke monster. The group finds him dying, and he tells Locke that "you're next."