When a psychic shriek for help nearly overwhelms the TARDIS, the Doctor and Belinda track the source to a distant planet. There they find a sentient, telepathic bioship named Adama and ragged colonists descended from the original crew. Adama is dying, and their spectral screams are growing strong enough to kill anyone in the vicinity. When Adama crashed 100 years ago, it was with a great treasure on board, stolen from the ruthless Gangnax Imperium - technology that could either unite worlds or destroy them. If they are to save the bioship, the Doctor and Belinda must survive suspicious colonists, greedy bounty hunters and military forces determined to reclaim what's theirs - before Adama's final death throes destroy them all.