 The group are interrupted and called to the ship's Darkroom when Kryten (Robert Llewellyn) discovers that the developing fluid has mutated, causing any photo it develops to come to life.Utilising slides to demonstrate the effect, Lister accidentally trips into a slide of a wedding photo, and discovers they can interact with the contents but cannot move beyond the borders of the original photo, learning that they can use this to travel in time when Lister interacts with one of Rimmer's old photos of Adolf Hitler.Lister quickly decides to use this method of time travel to change his life and make his younger self the inventor of "tension sheets", a product that one of Rimmer's former schoolmates invented that led them to becoming wealthy.