Feast of Amrita

A day trip turns into the ultimate nightmare when Tamahi, Aki, and Yu witness the shape of a woman falling from an abandoned apartment building. But it’s a trap, luring them into the "Carabi-Yau," a place where people disappear without a trace. Now they have to fight to escape, but as the fabric of time is shredded and looped by the monstrous things inside the decaying complex, the three girls can no longer keep track of their own memories… or even which of them is still human or already dead.

Synopsis from Anime News Network