I didn't know anything about the novel. I mainly watched it because I saw Timothy Spall's name. I found this movie engaging. Because of an element in the plot a large part of the movie has a surreal, dreamlike quality. The young female lead, Erana James, is very good. She has a fierceness that makes her character very believable. I'm not a huge fan of 'young adult' fiction. I usually find it condescending to its target audience but I got into this movie pretty quickly and it kept me to the end. Definitely worth a watch if you're channel surfing and come across it.
Review of The Changeover
