Ranma ½: Yomigaeru Kioku S01

Akane is afflicted with "memory regression" and remembers that when she was a child, she traveled to Rio Grande. There, she was saved by Shinusuke from a giant platypus. Akane returns to Rio Grande and sees Shinusuke again, who has fallen in love with her. Akane scolds herself for the dangers that threaten Shinusuke's life. This demon torments her and thinks Akane has fallen in love with Shinusuke, and she tries to do everything to get him back.