Fisher Stevens reprises his role of Ben Jahrvi, the co-inventor of the cute robot Number Five, in this sequel to Short Circuit. Since the last film, Ben has moved to the city, where he lives in a truck and sells toy Number Fives as a street vendor. Ben plies his trade until one day luck strikes in the form of Sandy (Cynthia Gibb), a toy buyer in dire straits who offers Ben $50,000 if he can quickly churn out a thousand toy robots. Offering to help the naive Ben is street con man Fred (Michael McKean), who becomes Ben's partner and finances the burgeoning enterprise through a loan shark. Ben and Fred begin to manufacture the toys in a warehouse; unfortunately, they soon find the building also houses the entrance of a tunnel dug by thieves, preparing to rob the bank across the street. With things appearing their bleakest, a crate arrives from Montana. Inside is the new and improved Number Five, who now insists on being called Johnny Five. Johnny Five has even learned to talk in a litany of phrases gleaned from television shows, and now helps Ben get started in the toy business. In the process, Ben and Johnny Five contend with the temptations and corrupt business practices of a big city environment.