Violent Night

In Greenwich, Connecticut, Jason Lightstone and his estranged wife Linda take their daughter Trudy to his mother, Gertrude's, mansion for a Christmas gathering. They overhear Trudy's Christmas wish for family unity through an old walkie-talkie. Other family members at the gathering are Jason's sister Alva, her boyfriend Morgan Steel, and her son Bert. Meanwhile, a drunk Santa Claus arrives at the estate, just as a group of mercenaries with holiday codenames, led by "Mr. Scrooge", raid the house and take the family hostage.
Startled by one of the mercenaries, Tinsel, shooting his weapon, Santa's reindeer are frightened off the roof. Tinsel is pulled out of a window and impaled on an icicle. Stranded, Santa resolves to rescue Trudy and her family from Scrooge, who wants $300 million cash hidden in a vault in the mansion. After killing the mercenary Frosty, Santa takes his radio and finds Trudy's channel. He then finds that the mercenaries are on his "naughty list". When Scrooge discovers that Trudy has been talking with Santa on her walkie-talkie, Jason denies Santa's existence, and a distraught Trudy runs past the kidnappers and successfully hides in the attic. Santa reassures her over the radio, revealing to her his ancient Viking warrior past as "Nicomund the Red".
Wounded, Santa is captured by Scrooge, who hates Christmas. Recognizing their real identities, Santa convinces henchmen Gingerbread and Candy Cane of his authenticity and escapes magically, although his magic sack is burned. Gertrude's "kill squad", led by Commander Thorp, arrives and kills Morgan—revealing their allegiance to Scrooge. Discovering an empty vault, Scrooge threatens Linda. Jason admits he stole the money, hidden in an outdoor nativity, and planned to flee with his family. Gertrude forgives him, revealing this as a Lightstone family rite of passage and naming him her heir.
In a shed, Santa finds a sledgehammer and eliminates the kill squad. Trudy sets up Home Alone-inspired traps, leading to Gingerbread's death. Santa kills Candy Cane before she can shoot Trudy. Alva, Linda, and Bert thwart Scrooge's order to kill hostages by killing Krampus. Scrooge and Thorp escape into the woods with Gertrude and the money, pursued by Santa, who kills Peppermint. Linda kills Sugarplum and Jingle, and Trudy witnesses her parents' reunion. Santa and Scrooge fight in a cabin; as they grapple, a badly wounded Santa magically flies up the chimney, mangling Scrooge's body and killing him. Thorp shoots Santa but is killed by a vindictive Gertrude.
Despite using some burnt money for warmth, Santa succumbs to the gunshot wounds. Trudy rallies her family to affirm their belief in Santa, healing him from death. Confused by the magic, but renewed in faith, Santa receives his returning reindeer, a note from Mrs. Claus, a new gift sack, and the return of his long-lost hammer, Skullcrusher. He bids Trudy farewell and continues his gift deliveries.
In a mid-credits scene, Bert vlogs next to Thorp's corpse, telling his viewers that Santa is real and warning them to behave during Christmas.