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.

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.