03E08 - Flashes Before Your Eyes

The episode opens with reminders about Desmond's premonitions: Locke's speech, the lightning rod, etc. In the present, as Locke and Sayid inform everyone about Eko's death, Desmond takes off running. He manages to save Claire from drowning in the ocean, but his prescience has now become obvious to Charlie and Hurley. They use some whiskey from Sawyer's raided stash to try and find out what happened to Desmond and get an explanation as to how, as Hurley puts it, "that guy see the future, dude." When Desmond passes out drunk, through his eyes we then begin to (re)experience his past and event leading up to why he did not end up with Penny, though he obviously still loves her and wishes things had been different. Triggered when Desmond "pushed the button," the flashbacks are actually a form of time travel or a replaying of events in an alternate/parallel universe. Desmond struggles with his sense of déjà vu and glimpsed of memories of the future as we see him living with Penny several years earlier in London, and his visit with her mean and snobbish father to look for employment. Soon, he must contend with choices and whether or not he can do things differently this time.