It has been untold years since the Giants-That-Were disappeared, leaving behind animals forever changed by their strange science. Now, granted the gifts of intelligence and self-awareness, the valiant Hamster Aquatic Mercenaries and their new allies, the Hamster Airborne Paratroopers, struggle to keep their hordes alive in a dangerous world. In The Underfoot: Into the Sun, H.A.M. and H.A.P. find themselves surrounded by disappearances and mysteries. However, the reveal of a third hamster colony brings new clues, and the three colonies must use their combined skills and knowledge to save their hordes from total destruction.