Dimension Jump (Red Dwarf episode)

"Dimension Jump" is the fifth episode of science fiction sit-com Red Dwarf Series IV and the twenty-third episode in the series run. It was first broadcast on the British television channel BBC2 on 14 March 1991, written by Rob Grant and Doug Naylor, and directed by Ed Bye. The episode, featuring the first appearance of Ace Rimmer, was intended to end the series but was changed due to the Gulf War conflict.

The episode begins with a young Arnold Rimmer being told by his mother that the headmaster at his school was considering keeping him back a year. Having received the headmaster's notice in the post, she emphasises what an impact the decision could have on Arnold's life. Years later, in a parallel dimension, another Arnold Rimmer exists. Commander 'Ace' Rimmer is a test pilot in the Space Corps: he is heroic, charming, good-looking, intelligent, popular, brave and modest. He eagerly accepts a mission to test-fly a dimension-jumping prototype spacecraft despite never being able to return. After saying farewell to his friends, Ace departs and initiates a dimension jump.

Aboard Red Dwarf, Lister, Kryten and the Cat attempt to sneak away in the middle of the night to enjoy a fishing holiday on a nearby ocean planet on Starbug and escape Rimmer for a few weeks. However, Rimmer discovers them trying to leave without him and is hurt, taking it as confirmation of their dislike of him. Lister feels he has no choice but to invite Rimmer along, to everyone's chagrin. Aboard Starbug, Rimmer soon irritates everyone, excessively commenting on Kryten's piloting, and trying to play Hammond organ CDs for Lister and the Cat. This is interrupted when Ace's ship emerges from a dimensional disturbance, colliding with Starbug.Starbug crash-lands on a water planet, but Ace follows to help, meeting his counterpart aboard Starbug. The two soon develop a mutual dislike, but by contrast Ace and Lister quickly become good friends and, despite Ace's broken arm, the two brave the elements to fix the craft while Rimmer stays aboard and makes snide jokes about Ace.