Denis, the most ordinary courier from Moscow, receives a seemingly unremarkable assignment: to deliver letters. But the familiar routine turns into a nightmare when he finds out that each message brings misfortune and death. Soon Denis realizes that his actions are being guided by someone’s hidden will, and that he himself is only a piece on someone else’s board, where forces beyond common sense play. Will he be able to stop doing this and choose disobedience? And what price will he have to pay for trying to break free? The answer waits behind the door of apartment number 24.