Following the events of Wizards, master wizard Hisirdoux "Douxie" Casperan and former Arcane Order member Nari lure their pursuers Belloc and Skrael onto a moving subway train in New York City where they launch a surprise attack with former Trollhunter Jim Lake Jr. and his girlfriend Claire Nunez. Jim is wounded during the fight while his best friend Toby Domzaski accidentally snaps the train’s brakes, causing the train to be unable to stop, and complicating things for Prince Krel Taron, Steve Palchuck and Stuart as they are tasked to use 'trifurcate radiation' to negate the wizards' magic.