Get ready to speculate.
Sony Computer Entertainment filed a trademark with Japan’s Patent and Trademark office for a new title called Sangeki no Sanso which translates into The Mountain Villa of Tragedy.
The title appears to be similar to the premise of Until Dawn given that it takes place in a mountain cabin where you are forced to survive as if you were in a horror movie. It’s also not unheard of for games to be given different titles in Japan then for other countries. Shadow of the Colossus was released as Wander and the Colossus in Japan and the Resident Evil series is known as Biohazard.
The problem with this theory is that Sony already filed for a trademark for Until Dawn in Japan literally one day before. The Mountain Villa of Tragedy may be a tagline, but that’s speculation at this point. We will keep you informed when more details become available.