Mystery Dragon - S3.E22

Aichi has an ominous nightmare in which Misaki, Kourin, Naoki, and Shingo all leave him. Worried about the dream, he then goes to school and is relieved to see his friends are there, except for Kourin. After school, Aichi arranges for the Cardfight Club to meet at Card Capital. Naoki goes back into the classroom to retrieve his bag and then decides to follow the student council's secretary. He is eventually led into a strange hidden room where he sees the secretary talking with an unknown person about monitoring the Cardfight Club. At Card Capital, Aichi expresses his worry to his friends over Kourin's absence. Naoki enters the shop, but he is acting like a completely different person. As if possessed by a dark force, Naoki challenges Aichi to a cardfight, which he accepts. The fight reaches a turning point when Naoki declares "Final Turn" and does a Crossbreak Ride with Eradicator, Vowing Saber Dragon "Reverse".