The Man in Black sends Sawyer on a reconnaissance mission to Hydra Island, where he discovers that Charles Widmore has returned to the island with a team of scientists. In the flash sideways, Sawyer is a lonely cop who is still searching for the original Sawyer.

After Jin is kidnapped and taken to Hydra Island by Widmore's team, the Man in Black confronts Widmore. On the main island, Sun loses her ability to speak English. In the flash sideways, Sun and Jin are abducted after failing to complete a transaction for Sun's father.

On the island, Widmore subjects Desmond to a large amount of electromagnetic energy as an experiment. In the flash sideways, Desmond, with the aid of Charlie, starts to have visions of his life in the original timeline.

The survivors split into two groups; one led by Sawyer, the other by the Man in Black. Sawyer's group travels to Hydra Island, where they are captured by Widmore's crew after Sun and Jin are reunited. In the flash sideways, the passengers of Oceanic 815 continue to cross paths with each other.