The mysterious organization Devil's Fang is unearthing the Crystal Skull Key from an ancient ruin in order to lure out Joker, when a mysterious shadow wreathed in flames emerges from a nearby stone coffin. Joker infiltrates Mr. Kaneari's Golden Museum in order to take the Crystal Skull Key as his 999th treasure, where he meets a boy named Akai Tsubasa, who seems to want to follow Joker around. Can they break through a gauntlet of perilous traps to get the key? And who is Akai Tsubasa, really?