A group of friends on a hiking trip happen upon a seemingly abandoned underground bunker. As they explore, they are trapped by an earthquake in its bowels. The next day, they discover water seeping into the bunker. They calculate that they have a week to escape, or they will drown. As the panicked group search desperately for a way out, they discover a way they can escape, but only by leaving one their number behind with little hope of survival. Then, one of their group is murdered.... And they won't be the last.The Ark will satisfy horror, mystery, and suspense fans with a thrillingly unraveled murder plot and escape arc, and a rug-pulling twist in its final moments.