Strange readings are detected by Spock while scanning the planet, Excalbia. These reading lead Spock to believe there is carbon cycle life forms on the planet. The scans are thought to be faulty because the surface is covered by a molten substance. However, the crew is surprised when deceased U.S. president Abraham Lincoln appears on the screen and invites them down.

The TARDIS materialises on a beacon station in deep space moments before space pirates break it up for its argonite. General Hermack of the Space Corps vows to stop the pirates by any means necessary, and when the grizzled old prospector Milo Clancey shows up in a restricted area of space, Hermack concludes that he must be involved in some way. In order to recover the TARDIS from the pirates, the Doctor, Zoe and Jamie must join forces with Clancey as he evades the Space Corps and tries to prove that the real leader of the pirates is the dastardly Maurice Caven. However, this proves more difficult when Caven is revealed to be in league with Clancey's rival, Madeline Issigri - and with her somewhat unwilling help, Caven plans to kill Clancey and his new friends and frame them for the pirate attacks, thus getting away scot-free with his crimes.