The Baxter family move from California to Maine and settle into their new house during the Christmas season. 10-year-old Finn Baxter (Christian Martyn) and his older sister, Alexis Baxter (Jodelle Ferland), are technophiles, who isolate themselves from their parents Curtis Baxter (Doug Murray) and Catherine Baxter (Ellie Harvie) and the outside world where Finn is playing his video game "Robo Infantry 3" and Alexis is always on her phone. Encouraged by his dad to socialize, Finn befriends his neighbor, Mason (Peter DaCunha), who informs him about the legend of a smothered gangster whose ghost haunts the Baxters' new home, leaving Finn paranoid.
While the family leaves their home to go shopping on Christmas Eve, a group of thieves led by Sinclair (Malcolm McDowell), Jessica (Debi Mazar) and their new safecracker Hughes (Eddie Steeples) carry out their plan to break in and steal an old, long lost Edvard Munch painting valued at $85 million, unaware the house is now occupied. They are unable to locate the painting in the basement safe, as the Baxters return home, and the thieves quickly flee. At night, Curtis and Catherine leave for a Christmas party hosted by Catherine's new boss, Mr. Carson (Edward Asner). Finn and Alexis stay behind; however, Finn's controller is confiscated by his parents. He is not permitted to play video games and Alexis can only use her phone for emergency calls.
That night after having seen the party invitation earlier, the thieves plan to return, thinking the house will be cleared of the whole family. Sinclair confides in Jessica and Hughes that the painting they seek is The Widow, a portrait of his great-grandmother and her family that was stolen decades ago. Meanwhile, Finn adventures in the house and finds a spare controller. He eventually breaks the rules by playing video games. Searching for new batteries for his controller, he accidentally drops one that rolls down into the basement. Finn has Alexis accompany him in the basement to retrieve it and they find the safe unlocked and a secret room behind it, which houses the painting Sinclair is looking for. Frightened by the portrait, Finn flees and Alexis accidentally triggers a trap and she ends up locked in the room.
As an ongoing snowstorm worsens, Curtis and Catherine are forced to stay at the Christmas party, worrying about their kids at home. With Alexis locked behind the safe, Finn goes to shop for supplies at a hardware store to break her out, only affording string that is useless. After stumbling across Sinclair, he overhears the trio discuss plans to break into his house. Rushing home, Finn tells his online video game friend and young college student, Simon (Bill Turnbull) about the situation, but Simon is initially oblivious to the situation. Finn sets up numerous booby traps around the house, and the thieves trigger them off one by one. Soon enough, Curtis and Catherine are able to drive home. Using Finn's gamertag and his parents' credit card details, a concerned Simon contacts them to warn about the danger their kids are in, but they call the police instead after thinking that Simon kidnapped them.
Back at the house, Sinclair, Jessica and Hughes capture Finn and detain him in the van. Sinclair and Hughes go to open the safe. Mason, however, saves Finn by throwing snowballs at Jessica, eventually incapacitating her. Sinclair and Hughes gain entry to the safe, finding both the painting and Alexis, who threatens to destroy it. Finn flees and frees Alexis, while triggering a trap that locks the duo in the basement as it is seen on Simon's television by Simon and the police officers present. With Jessica encased inside a snowman, the police arrive to arrest the burglars. The family receives four museum passes and $30,000 as a reward for capturing the criminals and recovering the painting that was made by the artist who painted "The Scream." As an apology, Finn's parents send Simon a plane ticket to return home and spend Christmas with his family.
On Christmas Day, Finn receives a snowboard and an expansion pack to "Robo Infantry 3" for Christmas. Finn decides to take a break from video games and go snowboarding with his friend Mason. The final scene has the criminals have their mug shots taken at the police station as a female police officer splices a copy of the mug shots into a portrait mug shot.