Hanna (Saoirse Ronan) is a teenage girl. Uniquely, she has the strength, the stamina, and the skills of a soldier. These come from being raised by her father, Erik Heller (Eric Bana), an ex-C.I.A. man, in the wilds of Finland. Living a life unlike any other teenager, her upbringing and training have been one and the same, all geared to making her the perfect assassin.