S1·E24 The Past, Once Again

Kogenta is dead, and Riku has lost all of his memories from when he was a Ten-ryuu Toujinshi. So, he doesn't remember Souma, Nazuna, or the boat club. Masaomi discovers that Riku's contract with Kogenta has not been cut. But, Riku seems to be rejecting his contract for some reason. To get Riku to accept his contract and restore his memories, not only will Kogenta have to be revived, but Riku will also have to walk down a difficult path, one that will reveal his ancient past.