Sheen was a prisoner of Hannah Brennan. He was operated on to become a living bomb. Bernice Summerfield tried to make him escape. He wanted Damien Colley to take him to Calabraxia so that he could destroy it. (AUDIO: The Secret of Cassandra) Retrieved from "https://tardis.fandom.com/wiki/Sheen?oldid=2668646" Categories: Human prisoners 27th century individuals Living weapons Community content is available under CC-BY-SA unless otherwise noted.