Gire was one of three astronauts living on the Moon. One Christmas, the moonbase was invaded by an energy creature and the Sixth Doctor and Evelyn Smythe.
At first the energy creature seemed to be attacking the moonbase, and the Doctor and Evelyn tried to help the astronauts defend themselves. When they realised the creature just wanted to communicate, they invited it in to celebrate Christmas. Gire suspected that the Doctor and Evelyn, who admitted they were from the future, had come to the moonbase to solve the mystery of the astronauts' deaths.
Gire and Jackson started a relationship that lasted when they all returned to Earth, where they eventually had a son. (PROSE: Christmas on the Moon)