When a deranged scutter badly re-wires Red Dwarf's circuitry the ship looks as if it's about to explode, and the only people who can override the auto-destruction mechanism are the dead captain and his officers.

Kryten has an idea to transfer the holographic brain information of one of them into Lister so that he can stop the ship exploding. The plan fails, but luckily the re-wiring has also taken out the auto-destruct detonation - not, Holly reveals, that there was a bomb connected to it anyway!

Still, the whole experience gets the crew thinking. Lister's been getting increasingly out-of-shape of late, and Rimmer's more than willing to put in the exercise and effort required to improve his diet and quit smoking. If they could just swap their minds for a couple of weeks...