I needed something to see, and since I'm such a fan of Helen Mirren, I picked this movie. It turned out to be an excellent decision. The film’s use of real time—we experience the events exactly as they happen—really creates suspense. The performances weren't particularly remarkable, but the story itself was very good. While watching, I found myself constantly debating with myself, wondering what I would do if I were in those characters’ situations. If you are trying to find a movie and have the opportunity to watch this one, just go ahead and start it without hesitation. Would I watch it again? Definitely! Would I recommend it to my friends? Without question!

Source on TMDB