Lidia, a young waitress from Romania, is lured to Sweden and trafficked into forced prostitution. She rebels by stealing from her pimps, and with the help from another Romanian girl named Alina, she hides money and other valuable items in a storage box at Stockholm Central Station - in Box 21. Police officers Ewert and Anni Grens are expecting their first child, but their happiness is dramatically cut short after a failed attempt to arrest the criminal Jochum Lang.