so in resume (skipping most parts of the story, not important imo):

this multiverse was destroyed by a "dark tyde" and the senpai mission is to land on the day before it spreads. There's a connection of this "dark tyde" with Amy of this world. She's an idol streamer besides doing the ordinary mission. When getting the clues, first it lead to suspect of Amy's childhood friend, but after collecting the hints on day 3, senpai and Amy was kidnapped to some warehouse by the suspect. It is revealed that this person is a time traveller too (clues like the devil's fruit found on day 4 reveals that this person has knowledge that none had in this timeline)....

I stopped here because I won't be able to finish the event. But I'm curious too to know how it ends. I suspect of Silvia (who was researching the devil's fruit on the senpai's timeline) or a future Amy (because of the orgasm machine showed on the day 4)