Set, like the previous films, in the fictional port town of Blue Bay, Marie Clifton (Laine) is set to inherit two beautiful diamonds, called the "mother and daughter". Marie's step-father, Jay Clifton (Johnson), challenges the will claiming that he believes Marie is not ready for the responsibility, but actually wishing to claim the diamonds for himself. At a sexual education seminar, physician Chad and probation officer Kristen Richards (Meyer) discuss sex crimes. Richards reveals that she was a victim of an anonymous rapist many years before.
Adam, a 23-year-old self-employed security technician, is hired by a businesswoman, Alice Comfort, to set up a security system in her flat. After finishing the work, Adam falls asleep on a lawnchair on her roof-garden. When Alice arrives home and finds him there, she impulsively asks him to accompany her to a housewarming party for her boss. He is unsure, but eventually agrees.
On January 1, 2008 at the Xcalibur Bowling Centre, a disco-themed bowling alley in Surrey, British Columbia, Egerton, the janitor, has allowed two groups of teenagers to bowl against one another after hours. The "prep", Steve, is still bitter after his best friend Jamie, the "jock", had sex with Lisa, a girl with whom Steve was smitten and even took to their senior prom. After Steve and his friends Joey, Patrick, and A.J. harass the "tranny", Sam, they are chastised by Jamie. This leads to a brawl between Steve's team and Jamie's. Lisa breaks up the fight by dropping a bowling ball on Steve's foot just as Steve is about to kick Jamie again. Egerton, brandishing a shotgun, tells the teenagers to leave and they can continue their tournament the following night.
Dans la nuit du 31 décembre 1799, dans une petite ferme isolée au Bas-Canada (Nouvelle-France), Espérance, femme mariée et ses trois jeunes enfants, reçoivent la visite de cinq soldats britanniques, dont l'un d'entre eux, sévèrement blessé, veulent passer la nuit à l'intérieur pour s'abriter d'un blizzard violent. Le père de famille, Pierre, étant absent pour aller au village voisin, Espérance doit protéger ses enfants de ces visiteurs indésirables qui font la fête pour célébrer l'arrivée du nouvel an. Mathurin, l'aîné de la famille, qui apprenait l'anglais, fait apprendre à sa mère que leurs invités se sont vantés d'avoir tué son père. Espérance veut se venger des meurtriers de Pierre, elle va devoir les éliminer un-à-un sans éveiller les soupçons de la part des anglais, elle doit assumer la responsabilité de protéger sa propre vie et celle de ses enfants.
Tess Thorne is a successful cozy mystery writer who has a fear of flying, and will only take speaking engagement miles away from her home. She goes to a Massachusetts library for a meet and greet with fans. After the event, the woman who had invited her, Ramona Norville, suggests an alternative route for Tess to take on the way home which would shave an hour off her drive. However, on the shortcut, Tess' Toyota Prius rolls over nail-studded pieces of wood which lie across the road, giving her a flat tire. The incident happens by an abandoned gas station. With her cell phone not having a signal, Tess hopes that a good Samaritan will stop.
Christine, who is about to marry Steven, decides to hold her bachelorette party in Las Vegas with her friends Olivia, Claire, and Barbara. Christine's foster mother bids farewell to her daughter, then bludgeons a bound and gagged man with a hammer. After the party, Christine's group begins driving back to Chicago in an RV, and it is revealed that Christine has a troubled past and an unspecified mental illness, which has caused her to carve inverted crosses into her abdomen. During the trip, the quartet pick up a hitchhiker named Joe, who they quickly eject from the vehicle due to his strange behavior. A short time later, the RV is flagged down by a religious police officer, who claims that she needs a lift to the nearest town.