Tricia and her husband, Ethan, drive through worsening snow toward a house showing in Westchester, but they lose GPS service and argue over the directions. Tricia believes Ethan has missed the turn for Cedar Lane, while Ethan refuses to admit he may be lost. The bad weather, the slick road, and Ethan's stubbornness make the trip increasingly tense.

As they continue, Tricia reflects on their six-month marriage and the speed of their relationship. She recalls meeting Ethan in a coffee shop, quickly ending her previous relationship, and marrying Ethan within nine months. Although she feels deeply in love with him and sees him as nearly perfect, Tricia also notes that Ethan does not yet know an important secret she is keeping.

Ethan eventually spots Cedar Lane and proves Tricia wrong about the missed turn. They drive down the narrow, snow-covered road and begin to worry that Ethan's BMW may not handle the conditions. When the house finally comes into view, both are struck by its size and beauty, and Ethan is instantly captivated by it as a possible home for their future.

Tricia expects to share Ethan's enthusiasm, but instead she is hit by intense nausea and dread. Looking at the estate, Tricia becomes convinced that something terrible has happened there. Before they can process the feeling, the BMW loses traction and becomes stuck in the snow.

Unable to drive farther, Ethan decides they should walk to the house. He assumes their real estate agent, Judy, is already inside because a single upstairs light is on, even though no car is visible and the first floor is dark. Despite Tricia's growing unease, the couple prepares to leave the safety of the car and approach the isolated house.