The Joker pulls off a string of key-related pranks throughout Gotham City, then with his magic box, proceeds to snatch a priceless jeweled key right under the noses of Batman and Robin. The Dynamic Duo wise up to his ways and thwart him at their next encounter. However, the Joker has more devious plans to do away with them both before his final caper.

After a reworking, the Joker's magic box holds the power to alter time forward and backward. Batman and Robin learn of his plans to pollute the city water supply, and butler Alfred is sent to take over as security guard at the water works. Alfred nabs the box upon the villain's arrival, freezing him and his cronies in time, but unwittingly commits a dangerous error when he removes the box's key.