Haise is a young boy who has been gifted with an unknown ability. He becomes an adventurer together with his childhood friend Sasha, but is kicked out of the team for being unable to use his ability and being a hindrance. Furthermore, while continuing his solo adventure, he is caught in a trap and falls into dire straits. Just as he is on the brink of death, Haise's ability "Weapon Master" awakens! It is a power that shakes the laws of the world, summoning weapons from another world!?