Lewis Smith who aspires to a be a mecha suit piloting hero from the American Marines and Ao Isami of the Japanese SDF are participating in a joint military exercise using Titanostriders (TS) mechanical suits deployed around the world in a test run. Suddenly the world finds themselves under attack by entities known as Deathdrives...

Lady Ameth predicted the Princess Knight named "Yuuki (Japanese for courage)" would appear one day with amnesia. Kokkoro is sent to find, protect and guide him but unfortunately, her funds weren't enough to get them by at the capital of Landosol. As they go questing to earn more money and continue adventuring, they meet a starving...