As they celebrate their high school graduation, four friends are involved in a hit-and-run accident when their car hits and apparently kills a pedestrian on an isolated roadway. They dispose of the body and vow to keep the incident a secret, a year later somebody starts sending them letters bearing the warning “I Know What You Did Last Summer.”

Sons and daughters of international billionaires are sent to an boot camp where they are taught basic survival skills in hopes it will teach them responsibility. When they are taken hostage and taken for ransom by kidnappers, they will need to utilize every skill they learned to survive.

A disgraced FBI agent with a drinking problem joins nine other troubled law enforcement officers at an isolated detox clinic in the wilds of Wyoming. But the therapeutic sanctuary becomes a nightmarish hellhole when a major snowstorm cuts off the clinic from the outside world and enables a killer on the inside to get busy.