The once civilised and populated planet of Jelsen was home to the Lords of Jelsen. They were emerald-robed creatures with round heads and glowing eyes. They used advanced technology housed in a tower to trap passing spaceships. The trapped spaceships and crew were then forced into a race through the city for the Lords' entertainment.
To make the game more exciting, the Lords manipulated the game from a control center, throwing in additional obstacles for the competitors. Obstacles included a fleet of N-fish — giant green square stingrays with tails as thin as hair. There was only one winner of the game. The losers were trapped in a ghost-like state.
The game was suspended for a while when the Tenth Doctor and Heather McCrimmon engineered a draw and disrupted the capture system by crashing a ship into it. In the disruption the Doctor brought back the crew and ships of previous players who made their escape. (COMIC: The Highest Stake)