Numbuh 699 was a drill sergeant in the Kids Next Door. He trained young cadets in the KND Arctic Academy and Prison. Later, he was sent to the KND Moonbase to meet with Sector Leaders and the Supreme Leader. After that, he returned to the Arctic Academy to then get sent to the Deep Sea Research Facility to stop the infected Teens and cure the infected operatives that were infected by the Chickenpox Virus. The battle was harsh, but in the end, it all worked out and 699 was sent back to the Arctic. A while later, he was sent with some other operatives, including Numbuh 78, to the Gregory Elementary School, where traitorous School President Jimmy McNixon, was located. They fought at the front door of the school intel more reinforcements arrived, and the Hall Monitors left the battle. Jimmy was later apprehended by 699 and was taken in.