[Crossover] I Lost My Memory After Forcing the Issue?

Hello, everyone. Here's what happened. This afternoon, after a long time away, I came to Yokohama to meet my best friend for lunch. On the way to Chinatown, I saw someone dressed completely wrong for the season jumping into the river. Out of basic human decency, I pulled him out. As soon as we got to shore, the man, who was a head taller than me, clung to my waist and accused me of seducing him and then abandoning him. Heaven knows, the last time I came to Yokohama was when my best friend started school, and I can't even remember the time before that. Could this be some new kind of honey trap? Pairing undecided. Theme: A story about a heroine who saves the world while uncovering the truth and mysteries surrounding herself.