When Lawrence heads out to attend a speaking engagement on antiques, he unwittingly finds himself participating in the L.O.V.E.M.U.F.F.I.N. Pageant of Evil against Dr. Doofenshmirtz and Rodney. As a special host oversees the proceedings, Perry is tasked with monitoring the situation, but Lawrence gets hit with Rodney's "Evil-izer," and is crowned the supreme leader of L.O.V.E.M.U.F.F.I.N. Meanwhile, Candace is determined to bust the boys but doesn't realize that they are actually helping with Mom's modern art installation. Across town, the boys are playing a giant game of darts.

Candace is bitten by a bat after watching a popular vampire movie with Stacy and worries that she is becoming a vampire. Phineas and Ferb's latest gadgets lead Candace to believe that she has indeed made the change from teenager to teen vampire. Meanwhile, Dr. Doofenshmirtz plans to change the Tri-State Area into a carbon copy of Gimmelshtump so that it will be easier to take over.