Plot: As Melancholy takes interest in a girl named Lotte and her intelligent dog named Rummy, Rook shows Kaito and the gang a newer Replica Ring model recovered from a manufacturing plant for Cubic to analyze. Melancholy equips Lotte and Rummy with Replica Rings and uses them to confront Rook in a puzzle, in which they must navigate a fog filled maze over a deadly drop, with the loser falling to his death