Saoirse Ronan will star in the indie drama How I Live Now.

Based on the novel by Med Rosoff, the film centres on Daisy (Ronan) a teenage girl from New York City who travels to England to spend the summer with family. When World War II breaks out Daisy and a younger girl named Piper must survive alone in the woods as they try to make it to safety.

Kevin Macdonald (State of Play) will direct.