In 2543, 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.
The surviving crew members escaped to England, where they found refuge in the village of Little Caldwell. Here, Admiral Summerfield established the Pyramid, a coffee shop and bookstore that doubled as a front for helping stranded aliens and temporal refugees like himself. Summerfield tried to stay out of the way of the Doctor, whom he feared. Bernice and the Seventh Doctor, though, found him in 1983, twenty years after he had gone through the rift. (PROSE: Return of the Living Dad)
Though he had made a home in 20th century England, Admiral Summerfield returned or was returned to his native time. He was present at the naming ceremony of his grandson, Peter Summerfield. A year or two later, he was manipulated into leading the Fifth Axis forces during their occupation of the Braxiatel Collection on the planetoid KS-159, but was later instrumental in the ultimate defeat of the Axis. His work done, he elected to return to Little Caldwell. (AUDIO: Death and the Daleks)
He had blond hair and grey eyes, and was relatively short in stature. Unlike his daughter, Admiral Summerfield preferred coffee to tea. He brewed strong Turkish coffee in a cezve that he carried with him at all times. (PROSE: Return of the Living Dad)