When the raft the survivors have been building mysteriously burns down, Michael is convinced that Jin is responsible for the sabotage, which only further escalates their rivalry. Meanwhile, Sun stuns her fellow survivors with a surprising revelation, and Boone gives Sayid a warning about Shannon.

Boone becomes concerned when Locke suffers physical problems while they try to find a way into the mysterious hatch. Meanwhile, Jack is reluctant to help when Sawyer starts to experience excruciating headaches, and Michael and Jin struggle to communicate while working together on the raft.