Kelly (Kaya Scodelario) and her boyfriend Mark (Daniel Boyd) have a very good relationship. One day, Kelly had a sudden idea to give Mark a surprise, so she sneaked into Mark's house without telling Mark. Who knew that what was waiting for Kelly was a group of vicious criminals. It turned out that the gangsters led by Karen (Ed Skrein) and Sean (Dougray Scott) chose the mansion where Mark lived as the target of robbery. Mark and his family were all controlled, but Kelly was an accident. The gangsters didn't know that there was such a free man in the house, which meant that the lives of Mark's family were all in Kelly's hands.