"When Mister Mxyzptlk starts pulling dangerous pranks all over Metropolis to get into the headlines, Superman uses his ties at the Daily Planet to trick the trickster into taking a serious time-out!" --Back cover.
When Bizarro decides to try to make a mess of the nice, clean city of Metropolis, Superman and his cousin, Supergirl, work together to foil his plan, but not before getting a little messy themselves.