Five years after concealing a murder, guilt-stricken summer camp counselors return in midwinter to the scene of their crime, now a utopian commune.
After a body is found and a guest vanishes, both groups discover they're trapped at the camp with communication to the outside world cut off.
As the list of victims continues to grow, the number of possible suspects narrows and the two groups are forced to cooperate despite mutual suspicion.
The histories of several characters unfold in flashback, revealing surprising connections, while an innocent hiker is pulled into the unfolding drama.
The gruesome past and false identity of a commune member is discovered, although it may be too late to save the fellow camper they have kidnapped.
Desperate to discover the identity of the killer preying on them, the remaining survivors reluctantly conduct a mock hearing to learn the truth.
Misinterpreted evidence points everyone in a false direction, while one camper finds evidence that makes him question the motive behind the slaughter.
The serial killer confesses to another camper, but the rest of the stranded survivors are still in the dark as final twists and truths are divulged.
On the first anniversary of a mysterious slaying, the masked killer responsible strikes again, butchering one of the earlier crime's eyewitnesses.
Connections to Kit are revealed in flashbacks, while a couple's secret affair is exposed via social media and another slaying strikes the community.
As school is dismissed for the summer, more shocking memories from the past year surface and a teacher who tries to be an ally to Saadia pays a price.
The Druid kills again as Amy recalls her role in Kit's death, Roberta questions multiple witnesses, and plans get underway for the solstice party.
Roberta and Pujit identify a suspect while Violet's lurid, exploitative murder blog goes too far, making her and Joe targets of outrage and revenge.
Attendees of the solstice party are stalked by the Druid while someone engineers a violent confrontation in the basement between Angel and Dan.
Angel and Dan desperately try to escape, Roberta and Pujit get too close to the Druid, and Saadia grows closer to Connor in the hours after the party.
With the identity of the Druid revealed, the few remaining survivors inside the apartment building must make a last-ditch fight for their lives.
While Dylan protests the local newspaper's coverage of his wife's return, Sarah meets her eccentric neighbors and some familiar figures from the past.
After she receives a cryptic message by mail, Sarah investigates the copycat with help from an unlikely ally. Robin has a close call with the killer.
Unpleasant truths haunt Robin, who faces steep financial penalties for Justin's crimes, and Brenda, who pays a high price for a long-ago misdeed.
The newest chief suspect becomes the latest victim, leaving the official investigators flummoxed, while the Executioner targets someone close to Cam.
Accusations fly when Sarah voices a theory about Cam's father and Cam fires back with one about her. Alison makes a bold move to grab the spotlight.
Tom Winston reveals troubling information about Sarah's past, while Vaughn takes great pains to conceal the truth about his own history.
Sarah learns the truth about her relationship with Dylan. To protect Sarah, Tom escapes from prison but finds he can't evade the Executioner.
As Sarah reels from Dylan's dishonesty, her hidden feelings for Cam surface, while the Executioner plots a bloody grand finale of a slaying.