The Battle is the Puzzle's Melody Phi Brain: Puzzle of God : Season 2 Episode 6

The Orpheus Order show up at Root Academy, revealing themselves to be students of Crossfield Academy, and challenge Kaito and the others to a duel in which, if they win, they will take possession of Kaito. They are brought to their hidden base where they must participate in a team sliding puzzle. Cubic loses the first round against Melancholy, but manages to gather some data to send to Souji. As Kaito prepares for the next round, FreeCell shows off a pendant that Kaito supposedly made a promise on.