: While submerged, Desmond sees the iconic "NOT PENNY'S BOAT" message on Charlie's hand from a previous timeline. This vision, later reinforced during an MRI scan, awakens memories of his life with Penelope Widmore.
On the Island in 2007, Charles Widmore brings Desmond back as the "package" required for his mission. Widmore subjects Desmond to a severe electromagnetic event—a test he survives because of his unique resistance to such energy. This survival is crucial; it triggers a "flash" of consciousness that allows Desmond to perceive the "Flash-Sideways" reality. After the experiment, a zen-like Desmond agrees to help Widmore, though he is soon intercepted by Sayid.
In the 2004 timeline, Desmond is Widmore’s right-hand man, living a materialistically successful but emotionally detached life.
: Tasked with retrieving a drug-addled Charlie Pace for a concert, Desmond experiences a near-death event when Charlie drives their car into the ocean.