Thirteen Magic Pumpkin Seeds

Finn Dagdaman's six-year-old life was saved with experimental robotic body parts, making him feel even more of an awkward misfit. When the military rediscovers his bionic abilities as an adult and offers to make him a fully bionic super-soldier, part of Finn yearns to be a hero like his brother. Then he meets a sassy witch with a daughter whose mischievous dog seeks out misadventures. In trying to rescue Batzy from his latest antics, they gather a zany cast of Halloween characters and are swept into saving a small country from a zombie apocalypse.
Who is behind these misdeeds, and can bionics and spells set things right before the Halloween clock strikes midnight?