In addition to an incipient fondness for greyhound racing, the young Arnau has two inseparable companions: a songbird and a fox. Both accompany him in his journey to adolescence, a difficult transition due to some hard circumstances: the mother of the boy is locked in prison, and he is forced to live with his uncles.

Raised by her father, an ex-CIA agent, in the wilds of Finland, Hanna's upbringing has been geared to making her the perfect assassin. Sent into the world by her father on a mission, Hanna journeys across Europe, eluding agents dispatched after her by a ruthless intelligence operative. As she nears her ultimate target, Hanna faces startling revelations about her existence.