After three million years of constant acceleration the Red Dwarf passes the speed of light. This results in "future echoes", events that will occur in the future than can be seen in the present. Rimmer sees a vision of somebody dying in an accident in the Drive Room, who he believes to be Lister due to a physical resemblance. It turns out to be Lister's second son, Bexley, that Rimmer saw in the accident, which will occur in twenty years or so.
Lister sees his 171-year old future self who then tells him to go to the medical room. There Lister sees himself a little older then he is now, holding two crying twin boys in silver foil. These are Lister's twin sons, Jim and Bexley, and the present Lister takes a Polaroid photograph.