Captain Ransom was an officer in the British Army during World War I. He was abducted by the War Lords and hypnotised into participating in their simulated version of the war, in which he served as adjutant to General Smythe. He and Major Barrington were hypnotised by Smythe to convict the Second Doctor, Jamie McCrimmon and Zoe Heriot of espionage, and Ransom later presided over the Doctor's attempted execution by firing squad.

He, like all the surviving victims of the War Lords, was returned home by the Time Lords. (TV: The War Games)