6 decades books

Nestled in the quaint town of Motochi stands an enigmatic duplex apartment. This peculiar building boasts two floors, both with a single, expansive room that spans the whole floor. Despite its striking appearance and unconventional layout, the owner of this seemingly ordinary abode remains an elusive mystery. However, a young man has stumbled upon an incredible revelation that has evaded the notice of his hometown. That the apartment is linked to countless other worlds, with currently five tenants from five different worlds.