In this adult-themed parody of the classic dark fantasy, a young, orphaned British boy named Luke is sent to live with his eccentric, cigar-smoking Norwegian grandmother after his parents die in a car crash. Nana Helga is a retired witch hunter, and she warns Luke about the terrifying reality of real witches: they are monstrous, child-hating females who disguise themselves as ordinary women. To spot them, one must look for hidden clues—wigs hiding bald scalps, square-toed shoes hiding feet without toes, and large nostrils used for sniffing out the scent of children.Seeking refuge from Luke’s escalating asthma, Nana takes him to a luxurious
seaside hotel in Bournemouth. Unbeknownst to them, the Royal Society for the Prevention of Cruelty to Children is holding its annual convention at the same resort. In reality, this gathering is a front for the Grand High Witch, a hideously cruel and powerful tyrant who commands the witches of England. Luke inadvertently stumbles into their closed-door meeting while hiding in the hotel’s auditorium.During a chilling address, the Grand High Witch reveals her ultimate master plan: to eradicate all children in England by utilizing a magical potion called "Formula 86 Delayed Action Mouse-Maker," which turns children into rodents so they can be squashed and exterminated by unsuspecting adults. To demonstrate the potion's efficacy, the witches capture a greedy, snack-obsessed local boy named Bruno Jenkins and feed him a bar of laced chocolate, transforming him into a squeaking brown mouse right before Luke’s eyes.Shortly after, Luke is discovered by the witches. They brutally capture him and force-feed him an entire vial of the mouse-making serum. The
transformation is instantaneous and agonizing, turning Luke into a spirited, intelligent mouse who retains his human mind and voice. Escaping the clutches of the coven, Luke reunites with Bruno and his grandmother, formulating a high-stakes, perilous counter-attack.Driven by fierce determination and a desire to save thousands of children, Luke and his grandmother sneak back into the witches' grand banquet hall. They successfully purloin a massive batch of Formula 86 and covertly pour it into the coven’s evening soup. The dramatic climax erupts into chaotic, R-rated and darkly comedic pandemonium as the entire congregation of witches consumes the tainted broth. One by one, the evil women violently transform into shrieking rodents. The hotel staff and guests panic, trapping and slaughtering the transformed witches, effectively neutralizing the national threat. With the Grand High Witch vaporized in the chaos, Luke, now permanently a mouse, embraces his loving grandmother. They resolve to spend Luke’s remaining years traveling the globe, hunting down and destroying the remaining pockets of witches worldwide, proving that courage matters far more than physical form.