Warren Patterson is an 8-year-old boy with allergies who has been enchanted by a magical jewel from a mysterious parallel world. Because of a spell that goes awry, Warren turns into a 7-foot-tall blue monster whenever he sneezes. He can't return to his normal form until he sneezes again, and it's anyone's guess when that may happen! Warren and his older sister Tracy also have to deal with the wicked Gorgool who wants to steal the jewel and use it for his own evil purposes; as well as the other unpredictable spells emanating from the jewel and its accompanying Book of Spells. Luckily, the kids have the help of their friend Johnny B. Dead, a ghost of a musician who secretly lives in the Patterson's attic. Warren and Tracy's parents are oblivious to all the magical happenings occurring under their roof, which makes for unending comic possibilities.