Flames Of Fiction (rewrite)

Takes place in an alternate universe of Omori, where Mari still lives and Sunny goes to highschool. In this universe, our gang hasn't met with each other. Mari was also considered a prodigy at piano in the age of 15. Because of that, she went abroad to have better education. 4 years later, where our story starts, she is going to come back home in almost a week.Sunny is excited for his sister's returnal, but thinks that there won't be anything out of ordinary other than that. All he has to do is endure some boring school days for a while......But things take an unexpected turn for Sunny when he somehow steps into an unknown and honestly weird place called "Headspace". And now, he needs to uncover the secret of this place as he makes some friends along the way.