Humanity is under siege from the earless. As a result, it appears that humans have forgotten the concept of music. However, there are people with large auxiliary ports on their body. This allows them to plug into equipment, which turns into a giant mech to fight the earless. One day Echo saw a part that he desperately wanted. Well turns out it was attached to a player. Now he gets to take his homemade equipment and travel the world-saving it one song at a time.