After losing a bet to two kids, Grim, one of the people given the title of The Grim Reaper, is forced to be best friends with Billy Atoms and Mandy Maxwell for all of eternity. But Billy and Mandy end up discovering the plans of a villain known as Estroy, who is also teaming up with Dr. Tenma and President Stone in a plan to create a robot designed to level cities and allow the three to rule the world
