Dennis discovers that Ralf the janitor is the legendary Prankmaster General and is told he could become his successor. Walter won't let this happen and challenges him to a prank battle to win Ralf's book of pranking - the infamous Prankypedia.

Walter attempts to ruin The Dinmakers' chance of reaching fame. He will stop at nothing - even wearing a frock, and pretending to be a fan called Wanda who loves Dennis in order to break up the band!