The titular main character, Omori, awakens in the "White Space", a small white room he has lived in "for as long as [he] can remember." He enters a door to the vibrant world of "Headspace", where he meets his older sister Mari and his friends, Aubrey, Kel, Hero, and Basil. They look through their shared memories through Basil's photo album and then decide to visit his house, with Mari staying behind.