Jervis Tetch, The Mad Hatter, sets out to take revenge against The Batman and the 12 members of the jury that convicted him and sent him to prison. Using The Super Instant Mesmerizer concealed in his top hat, he begins stealing hats of the jurors--along with their owners! After collecting most of the jury, Tetch decides it's time to add Batman's cowl -- his "thirteenth" hat, he calls it -- so he sets a trap for The Caped Crusader and Robin the Boy Wonder at the studio of sculptor Octave Marbot, who is currently sculpting a statue of Batman.
Masquerading as Marbot, Tetch tries luring The Dynamic Duo into removing his cowl so he can use it as a model for the statue's head. Knowing full well that Marbot has finished the head already, The Batman sees through The Mad Hatter's disguise, and, pretending to fall for his deception, The Dynamic Duo retire to the back room to remove The Batman's cowl in secret. There they find the real Marbot bound and gagged in the closet, and burst out to confront The Mad Hatter. During the battle that ensues, Tetch tries his Super Instant Mesmerizer on Batman, but the latter counterattacks with his Antimesmeriszing Batreflector; unfortunately, The Hatter dodges and Robin, standing behind him, is hit by the deflecting ray. Rushing to his aid, Batman is knocked asunder by Jervis Tetch, who manages to entomb The Caped Crusader in Super-Fast Hardening Plaster!