Lauren returns to her flat after a night out celebrating her friend Elena’s upcoming wedding to discover a strange man on the staircase. She rushes outside as he calls her name. Lauren grabs her cell phone and—just before the phone’s battery dies—sees that she and the man are pictured on its screen. She notices, too, that she is suddenly wearing a wedding ring.

The man brings her a glass of water and some pajamas; Lauren prepares to sleep on the sofa. She secures a chair underneath the door to prevent the man from reentering.

Lauren wakes and the husband is cooking in the kitchen. After dressing, she agrees to eat a sandwich that he sets in front of her, surprised by how good it is. Several things within her flat have changed, though a few are the same. She tells the husband that she is going to take a walk to clear her head. While out, she scrolls through her phone, finding photos of the night before, but also photos of the husband as well as messages from him. His name appears to be Michael. After speaking with her neighbor and doing some googling, Lauren discerns her wedding date, her husband’s last name, and the architecture firm he works for.