Two men fortify a nondescript British apartment so it can serve as a prison, and then kidnap a woman and tie her to a bed. Who are these two men? Why have they kidnapped Alice? What is their relationship to each other, and to her? Each leap to the next answer reveals new pieces of the puzzle but complicates the overall picture. And even when the players are known, there are still new surprises in store. Vic (Eddie Marsan) is hard and remorseless, but his dominance over the younger Danny (Martin Compston) turns out to be shaky. And although Alice (Gemma Arterton) is terrorized by the plight she wakes up to, her feral intelligence takes over and shifts the balance of power again.