Contains spoilers for this episode and earlier episodes.
The helicopter’s journey to the freighter leaves Desmond unable to recognize Sayid or remember his island life. His consciousness moves between the ship in 2004 and his military service in 1996. These are experiences he actively lives through, rather than ordinary remembered flashbacks. On the ship, he meets Minkowski, who suffers similar displacements. Daniel speaks to Desmond by telephone and tells him to find Daniel’s younger self at Oxford when he next returns to 1996.
At Oxford, Desmond gives Daniel the settings supplied by his future self and mentions his experimental rat, Eloise. The experiment sends the rat’s consciousness through time, allowing her to run a maze she has not yet learned. When Eloise dies, Daniel tells Desmond he needs a constant: someone or something present in both periods. Desmond chooses Penny, but first needs a way to contact her from the freighter.
In 1996, Desmond obtains Penny’s address from Charles Widmore and persuades her to give him her telephone number. He asks her to keep it unchanged until his promised call in 2004. On the ship, Sayid repairs the damaged communications equipment while Minkowski dies. Desmond reaches Penny, who says she has been searching for him and still loves him. After the call, Desmond recognizes Sayid again. Daniel’s journal contains a note naming Desmond as his own possible constant.