In 2252, Charlie was the sole survivor of a transport crash on the planet Thasus. Charlie, who was only three years old at the time, was raised by the Thasians, a noncorporeal species. Charlie claimed to have survived by learning from the ship's computer tapes, but it was later found that the Thasians gave Charlie extraordinary mental powers in order for him to survive on Thasus. At the age of 17, Charlie was rescued by the crew of the science vessel, Antares. He was then transferred to the U.S.S. Enterprise. His social inexperience combined with his mental powers made him too dangerous to live with humans, so the Thasians took him back to live on Thasus.