Three kids pilot a robot made of material nobody understands, living in a shelter where their real memories were stolen. The show never wastes an episode, building them as actual people before asking them to save what's left of humanity. The mecha designs look awkward on purpose, like teenagers jury-rigging salvation from broken world scraps.

Humanity survives in shelters after a mysterious alien force called the Dracters wipes out nearly all of the human race. Inside the shelter Ixia, residents lead ordinary, monitored lives with their memories of the day of destruction erased. A select few are chosen to pilot giant robots and fight the aliens. Three teenagers from the shelter are picked to fly three machines that combine into Musashi, a robot built from Megatronium alloy. Mecha battles alternate with school life in this science fiction series.