Numbuh 5 is sick at home with the flu, and Numbuhs 1 and 2 take it upon themselves to protect her from the enemy. While at her house, her father lets it slip that teenage sister Cree is wearing a training bra! Ever suspisious of teenagers, Numbuh 1 figures that this odd device must be "Battle Ready Armor", and becomes determined to discover the workings behind it. But when the two of them are discovered, can even the Kids Next Door survive the wrath of a humiliated teenager?! And could there be more than meets the eye in this lingerie liason?