Series 2, Episode 19
Bernard takes matters into his own hands when he announces he wants to send a signal to would-be rescuers by building a huge S.O.S. sign on the beach out of rocks. But his plans are jeapodised by Rose when she embarrasses him over the idea. Through the flashbacks we see how Rose and Bernard met and her failing health. In the jungle, Jack and Kate set off to find The Others to offer them an exchange - Henry Gale for Walt... but they get a surprise when they receive somebody else instead.
Weak episode, which I think is due to the focus being on two minor characters.