Admiral Summerfield supposedly deserted during a space battle against the Daleks in which he disappeared. Most assumed he had died in the battle. (PROSE: Love and War); his ship, the Tisiphone, disappeared towards the end of the battle and was never seen again. The Tisiphone had, in fact, survived — it had fallen into a rift in space-time and was transported, along with its surviving crew, to Earth space in November 1963.