
The Hatch is explored. A familiar face is inside.

The raft survivors struggle to stay alive at sea.

The DHARMA Initiative orientation film is discovered. The button's purpose is explained.

Hurley is put in charge of the Hatch food supply. The tail section survivors are introduced.

Sun loses her wedding ring. Jin joins a search party.

Shannon's past is explored. The tail section survivors merge with the main group.

The story of the tail section survivors is told from the beginning.

Ana Lucia faces consequences for Shannon's death. The groups merge uneasily.

Kate's original crime is revealed. A missing piece of the orientation film is found.

Mr. Eko confronts Charlie about the Virgin Mary statues. A face-to-face with the Monster.

Jack leads a search party after Michael runs off. The Others draw a line.

Charlie has disturbing visions about Aaron. His rockstar past is explored.

Sawyer pulls off a masterful con to gain control of the camp's weapons.

Rousseau captures a man who claims to be a balloonist. Sayid interrogates him.

Claire recovers memories of her kidnapping. She searches for a medical station.

Sun discovers surprising news. Henry Gale's story is investigated.

Locke is trapped in the Hatch during a lockdown. A hidden map is revealed.

Hurley sees an old friend from the mental institution. Reality is questioned.

Bernard wants to build an S.O.S. sign. Rose reveals a secret.

Michael returns with a plan. Shocking violence erupts in the Hatch.

Eko and Locke search for the question mark from the blast door map.

Michael's time with the Others is revealed. The funeral for the dead.

Desmond returns by sailboat. His backstory reveals how he came to the Island.

The season finale. The button's truth is tested. Michael makes his choice.