One-shot: Marshmellow is the head of a gang of thieves known as Mitsukubi Condor, and he is obsessed with beauty. One day, a girl named Cocoa comes to him, trying to find the harp that was precious to her village. He decides to help her recover the valuable harp, which plays beautiful music that can draw out rainbows! Series: Many years ago, an evil witch ruled the continent, and she had many magical treasures. Now the land is ruled by a king, but the witch's treasures remain. A young amateur thief named Sue is determined to sneak into the nearby ruins and steal treasure to help her poor village. On her way, she runs into one of the 3 legendary thieves, Marshmellow, who is obsessed with beauty. He isn't quite as suave as she'd expected, but he seems to have the same eyes as the ancient witch. After their first adventure together, Sue joins him on his journey to collect all the witch's treasures. He claims he is only interested in their beauty, but what will happen if he actually recovers them all?