Christmas Eve. De Costa and Perkins investigate an assault after tempers flare following an office Christmas party, but when the defendant claims he was sexually assaulted by his female boss the night before, the pair investigate a subjected campaign of bullying which appears to have taken place prior to the attack. With the defendant denying all knowledge of the attack, Perkins is forced to tow a hard line in an attempt to get her to talk. Meanwhile, Harman and Fletcher encounter a homeless young man who is trying to find a shelter to sleep at over the Christmas holidays, but Fletcher suspects there is more to the case than meets the eye – and discovers the man has a wife and child.