Devon is always being left behind by her genius twin sister, Drew. At this point, it's a fact of life. But Devon has one last plan before Drew leaves for college a whole year early - The Best Summer Ever. After committing to the bit a little too much, the twins and their chaotic circle of friends learn why you don't ever mess with a Ouija board if you want to actually survive the Best Summer Ever, and soon find themselves being hunted down by - a demon? But while there's no mistaking the creeping, venomous figure is not from around here, their method doesn't feel very demonic at all. In fact, it's downright human - going after them in typical slasher movie kill order. And that means Devon, the blonde, is up first and her decade-long crush, Yaya, is the Final Girl who must kill or be killed to end the cycle.