Luke and his brother have swapped bodies by accident. Zack's got Luke's weird feet while Luke has Zack's SUPERPOWERS! Now he needs another world-threatening adventure to try them out. Could a family mini-break at Great Minds Leisure Park be his chance? Probably, because that's where his super-clever arch-enemy lurks, fermenting dastardly plans and bubbling gently... 'My Arch-Enemy Is a Brain In a Jar' is the fourth instalment of Luke's laugh-out-loud adventures. From the author of 'My Brother Is a Superhero', winner of the Waterstones Children's Book Prize and the British Book Industry Awards Children's Book of the Year, and 'My Gym Teacher Is an Alien Overlord', winner of a Lollies Laugh Out Loud 2017 Book Award.