Plot summary
To test if Desmond can again survive, Widmore subjects him to lethal electromagnetism that sends him to 2004, where he is Widmore's trusted assistant and meets Claire at LAX. He is tasked with bringing Charlie to an event where Daniel, a musician, will be performing with him. Charlie tells him that, while choking, he saw visions of himself with Claire, and drives Desmond's car into the water in order to see her again. Desmond rescues him but starts having visions of his time on the island. He hears that Penny Widmore is on the guest list for Daniel's event; Eloise Hawking forbids him from looking further, but Daniel tells him that he has also been seeing the island and directs him to Penny.
Desmond passes out when she shakes his hand and wakes up in 2007, where Sayid rescues him. Back in 2004, Penny accepts his offer of a date and he goes after the Flight 815 manifest, saying that he needs to "show them something."
Credits
Adapted from Wikipedia contributors, Lost season 6. HTML formatting and reference markers removed.