At a vacation winter lake house, seven high school seniors are attacked by a madman out for revenge.

Ash and Max must question the future of their relationship when Max gets accepted into an East Coast graduate school program. On their final night together, they relive moments of their past before they're interrupted by a surprise going away party.

After the simple night in Vanessa had planned for Duncan's birthday goes south, things get increasingly worse as guest after uninvited guest begins to show up to the celebration - the result of a mass text gone awry.