Owarinaki Gogo

A man wakes up in a pile of rubble without any memories. Confused, he stumbles upon an entranceway with stairs that lead down into a strange facility littered with bodies. After a woman calls out to him for help, the two make their way to a time machine to travel back to 20th-century Tokyo—where the man allegedly came from. But upon returning to his supposed world, the man begins to question his way of life and whether this truly is the place he calls home.