K.C. goes undercover as a male cadet with Ernie to rescue an agent's son at an all boys' cadet academy.

Ernie and Judy go to New York City to intercept an evil wolf serum, but their mission is interrupted when they run into Emma and Zuri ("Jessie") at a Halloween party. Meanwhile, Marissa and K.C. throw their own Halloween party at home, and K.C. dresses up as a spy to impress a new boy at school.