Somewhere on a far away island lives Shiro, a small, cuddly creature with very special abilities. His favourite hobby: collecting magic fireflies, the so called Lumies, and storing them in his charmed lantern. Unfortunately, our furry friend is quite a clumsy fellow, so it is no wonder that he manages to one day break his precious lantern! All of the Lumies escape into the air and settle throughout the four worlds of Gravity Island. Of course Shiro immediately sets out to find and collect his dear pets!