Sally Sanban is the daugther of Numbuh 3, as seen in Operation: F.U.T.U.R.E. In this alternate future, the villainous Madam Margret had turned most of the earth's male population into girls. Sally, however, had heard stories from her grandmother about how, long ago, girls and boys used to play together. She is a dreamer just like Numbuh 3. Numbuh 3 is Sally's grandma.
Posing as a boy, she attempted to join the Boys Next Door and help fight Madame Margaret. She was found out, however, when it was discovered she inherited her grandmother's fondness for Rainbow Monkeys. The Boys Next Door were about to dispose of her until an elderly Numbuh 4 intervened.