Archaeologist Shauna Hegarty is looking forward to a working holiday in the Scottish Highlands, but events take a serious when Shauna and her friend Tessa are kidnapped by violent thugs while exploring underground. Their nightmare has only just started - the gang makes money by forcing women to kill each other for an audience. The prospect terrifies Shauna, until she is forced into the 'arena' with another woman. Then she has to come to terms with a terrifying concept of enjoying the killing.