Carradine was a scientist and assistant to Professor Rayner. Together they grew tropical plants at the Carradine Estate and discovered the secret of controlling plant life. When Carradine learned of Rayner's Master Plant and his plans to use it to rule, he tried to flee, but was recaptured along with the Third Doctor and Dave Lester. After the Doctor defeated the Master Plant, Carradine planned to report Rayner's disappearance to the authorities. (COMIC: The Plant Master)