A parasite leaves Archer unable to form new memories, and in a grim future where Earth was destroyed, T'Pol cares for him.
Archer is infected by an extra-dimensional parasite and loses the ability to form new long-term memories. He wakes years into a future in which the Xindi have destroyed Earth and a small surviving population of humans lives on Ceti Alpha V.
T'Pol has devoted years to caring for him, and the two have developed a deep bond. Phlox has learned how to remove the parasites, and the surviving crew try to change history. Their success erases the grim future. The episode was directed by Robert Duncan McNeill and written by Mike Sussman.