Louie the Lilac has cornered the flower market in Gotham City, hoping to gain control over the entire "flower generation." He kidnaps the organizer of their planned flower-in, Princess Primrose, and brainwashes her with his Stupefying Aromatic Spray. Batman and Robin follow a clue to the villain's lair only to be captured by Louie and fed to his giant man-eating lilacs. With the Caped Crusaders out of the way, Louie heads back to the flower-in to continue his evil plan.