Based on Nicci French's best-selling novel, this thriller centers around a newly dating couple, Miranda and Brendan (Kate Ashfield and David Tennant), whose steamy romance comes to a screeching halt after she catches him reading her diary. Miranda abruptly ends the fling, but Brendan refuses to be broken up with, employing bizarre revenge tactics and infiltrating every aspect of Miranda's life -- until things take a turn for the deadly.