When Bobby fails to be cast in the school musical, he purchases a set of tarot cards at a local flea market to take up as a hobby. Hank mistakenly thinks Bobby has taken up playing cards, not reading them, and is thrilled that Bobby has finally found something cool to do.
Hank becomes even more excited that Bobby has found a new group of friends to hang out with, but is upset and ashamed when he learns that these "friends" are just geeks into black magic and wizardry. Hank becomes worried about Bobby's new interest in the "black art." Not because it's evil, but because it's for nerds- he realizes Bobby has found a new way to become a nerd that he didn't see coming.
Bobby is offended because he identifies with these guys and continues to hang out with them to defy Hank. The warlocks decide that they need to take their magic to the next level so they'll be taken seriously and they nominate Bobby to drink some dog blood they stole from a vet.
When Bobby wavers, they threaten to put a curse on them. Bobby realizes that if he drinks the blood he'll be forever humiliated so he takes a wild stab, and derides the warlocks as nerds, just like Hank did, and saves himself just as Hank and Dale arrive.