Team Scorpion must find a boy from Ralph's class who goes missing on a field trip after he accidentally has a run-in with a deadly criminal. Also, Toby gets closer to finding out the identity of Happy's husband.

Before Halloween, Team Scorpion must infiltrate a deep, vast cave system in order to prevent a bat population from destroying the North America ecosystem. Also, the team does costumes to stage photos from Halloween's past for Walter's upcoming immigration inspection.