Plot

A deranged masked Santa-Slayer comes to town for some yuletide-terror. He leaves behind a bloody trail of mutilated bodies as he hunts his way to the front steps of the town's most feared and notorious home.

ALL THROUGH THE HOUSE is an 80s-style slasher film featuring a deranged Santa Slayer who rips through the town of Napa, California for some yuletide-terror. Fifteen years ago, a peaceful Christmas neighborhood was engulfed by fear when five-year-old Jamie Garrett was mysteriously taken from her bedroom never to be seen again. Now on Christmas break, Rachel Kimmel comes home from college to find her neighborhood struck again by a reign of terror. A violent killer is hiding behind a grisly Santa mask, leaving a bloody trail of slaughtered women and castrated men to the steps of the Garrett house. Rachel finds herself in a horrifying nightmare as she discovers the twisted secret behind the mask.

An unidentified killer dons a Santa Claus suit and mask stolen from a Christmas display outside Sheila's house. Sheila's young son Jacob opens the door. Using a pair of garden shears, Santa kills Sheila as she showers and then castrates her husband.

Rachel Kimmel returns to her hometown to visit her grandmother Abby for the holidays. Rachel spends her first night back going out with old friends Gia Wilson and Sarah Hayes. Rachel is uncomfortably surprised to discover Sarah arranged a brief reunion with Rachel's ex-boyfriend Cody.

Santa goes on a killing spree throughout the neighborhood, killing women and castrating men. Meanwhile, Abby's odd neighbor Mrs. Garrett secretly treats mannequins in her home as if they are her former husband Mitchell and daughter Jamie, who mysteriously disappeared 15 years earlier.

To playfully take revenge on her friends for setting her up with Cody, Rachel forces Gia and Sarah to help her decorate Mrs. Garrett's home because she feels sorry for the lonely woman. Mrs. Garrett goes out for the night, leaving the women alone.

Sarah goes to get groceries. Rachel finds a photo indicating that her deceased mother Laura and Mrs. Garrett worked as nurses together, despite Mrs. Garrett claiming she barely knew Laura.

Santa strangles Abby in her home with holiday lights before rolling her off a cliff in her wheelchair. Shortly after, Rachel goes to her grandmother's house to check on Abby.

Sarah returns to Mrs. Garrett's house. Santa kills her outside. He then enters the house and kills Gia with his hedge trimmers.

Over the phone, Rachel tells Cody about love letters she discovered indicating that her mother had an affair with Mrs. Garrett's husband Mitchell. By the time Rachel returns to the empty Garrett house, Cody calls back to tell her that Mitchell was sent to Ironwood State Prison around the same time Jamie Garrett disappeared.

Mrs. Garrett confronts Rachel. Mrs. Garrett claims that Mitchell tried to kill Jamie because she was born a boy. However, Mrs. Garrett confesses that she actually castrated Jamie herself and framed Mitchell for the mutilation. After the ordeal, Jamie was committed to a mental hospital and has now returned as the killer Santa. Mrs. Garrett additionally admits that she murdered Laura Kimmel. Rachel falls unconscious from drinking drugged egg nog.

Rachel wakes tied to a closet rod. Jamie attacks, but Rachel is rescued by Cody. Injured in his confrontation with Jamie, Cody is forced to hide. Rachel escapes by jumping out a window. Jamie chases after her.

Rachel eventually returns to the house where she fights with Mrs. Garrett. Jamie captures Rachel and puts her in a cage alongside Cody, who is now tied to a table. Jamie presents his mother with a sack full of severed penises.

Mrs. Garrett privately tells Rachel that she plans to kill Jamie. She blames Rachel for being the daughter she should have had, revealing that Mitchell Garrett is really Rachel's father. Mrs. Garrett then kills Cody with the shears.

Mrs. Garrett tries stabbing Jamie by the Christmas tree in the family room, but he fights back. Rachel gets free and watches as Jamie strangles his mother. After Mrs. Garrett dies, Rachel tells Jamie that they should bury her out back. Rachel examines a painted portrait of Jamie before removing the Santa mask he left on Mrs. Garrett and throwing it outside.