A murder investigation frozen in time is beginning to melt. November 1993. Scotland is in the grip of an ice-cold winter and the Lake of Menteith is frozen over. A young man and woman walk across the ice to the historic island of Inchmahome which lies in the middle of the lake. Only the man returns. In the spring, as staff prepare the abbey ruins for summer visitors, they discover the body of a girl, her skull violently crushed. Present day. Retired detective Alan Narey is still haunted by the unsolved crime. Desperate to relieve her ailing father's conscience, DS Rachel Narey risks her job and reputation by returning to the Lake of Menteith and unofficially reopening the cold case. With the help of police photographer Tony Winter, Rachel prepares a dangerous gambit to uncover the killer's identity - little knowing who that truly is. Despite the freezing temperatures the ice cold case begins to thaw, and with it a tide of secrets long frozen in time are suddenly and shockingly unleashed.