A young woman is frantically packing bags. She bolts out of the door leaving behind the apartment keys and an engagement ring. Once on the road, she receives a phone call from her boyfriend Bob (Bradley Cooper). Michelle (Mary Elizabeth Winstead) and Bob had a fight. Michelle did not need to storm out. The two could have worked things out.

Michelle is running away. To where, she has no idea. She drives and drives on two lane roads until she has no idea where she is. The news on the radio mentions a power outtage affecting the Eastern seaboard of the U.S. Wham!

Michelle is involved in a car accident. She wakes up in a cement-block room. Her arm is attached to an IV line. Her pants, shoes and socks have been removed. A brace is wrapped around her right knee. The brace is chained to a pipe embedded in the wall. Michelle is a prisoner. Who holds her captive? What does he want with her? Why is she captive? Where is she? What can she do about her situation? How long will she be confined?

Meeting Howard (John Goodman) doesn't improve Michelle's situation. Howard tells her there has been an attack. It might be nuclear, chemical, or both. He has no idea how bad things are. They are both prisoners, but they are both safe. It is a plausible explanation. However, Michelle has no way to corroborate his story. Worse, Howard isn't sure if the attack is by the Russians or the Martians. Howard tells her no one is looking for her. According to him, everyone she knows is already dead! Yep, Michelle is in deep trouble.