Corporal Gibbs was a soldier stationed in Singapore during World War II. He served under Captain Freeman.
In February 1942, an ambush by the Forsaken killed several soldiers including Freeman. Gibbs, Lawson and James Jackson were the only survivors and took refuge in a hotel owned by Maggie Bishop. Unknown to them, the Forsaken took the form of Captain Freeman.
After the Second Doctor defeated the Forsaken, Jackson and Gibbs were rescued by a boat. (AUDIO: The Forsaken)