"Live Together, Die Alone" is divided into three main story lines, and each one of them alone would have been enough for a great episode. So when you put all of them together, you have a great ^ 3 episode. It was a daring move to give the flashbacks of a season finale to a character (Desmond) who had only appeared in 3 episodes up to that point, but it worked: his backstory is absolutely fascinating to watch, both informative about the past of the island & the Swan station itself and honestly moving. Desmond and Penny seem magically connected to each other, even when they are on opposite ends of the world, and both characters are beautifully acted (it's hard not to cry when Desmond reads Penny's letter). The action inside the hatch is edge-of-your-seat tense, as Locke is determined not to allow the button to get pushed again, convinced it was all just a psychological experiment, Desmond gradually realizes the consequences of this decision, and Eko is locked outside and tries desperately to get back in. The melting of the clock and Locke's "I was wrong" are unforgettable moments. The outside action has Jack, Kate, Sawyer and Hurley captured by the Others due to Michael's betrayal (after they make a puzzling discovery connected to the Pearl), and "Henry Gale"'s game-changing return as the Others' leader. Even the least important plot line, Sayid, Jin and Sun sailing to the beach where the Others are supposedly camping, contains one of the greatest mythological mysteries of the show, the giant statue that's almost entirely missing except for a foot with four toes. In short: emotion + history + mythology + adventure + suspense + the threat of annihilation + a ray of hope = a classic LOST episode. ***1/2 out of 4.