Arriving home from a basketball game, Arnold Shortman and his best friend Gerald Johanssen learn that Alphonse Perrier du von Scheck, the CEO of FutureTech Industries (FTi), has announced plans to redevelop the entire neighborhood as a luxurious high-rise shopping mall. That night, Helga Patiki finds that her father, Big Bob, is working with FTi to build a new super-sized branch of his beeper store in the proposed mall. She ultimately sides with her father, though is hesitant to do so because of her love for Arnold.

Picking up where Hey Arnold! (1996) left off, this tells the story of what happened to Arnold's parents.