When someone hacks Sheldon's online gaming account, the guys go on a quest to find the culprit.
When a young woman is shot to death, Beckett and Castle learn the gun used was the one a serial killer stole from Detective Ryan.
Juliet must reveal some surprising news to Jin when Sun threatens to move to Locke's camp; Desmond and Sayid meet the ship's captain and begin to get an idea of the freighter crew's mission.
When an FBI agent who was cracking down on organized crime is killed, McGarrett rounds up every gang-related criminal on the island to find the culprit responsible for the murder.
Alex is jealous that Jerry is giving so much attention to Maxine.