Gary Lowbow and rookie detective Iana Elmo are assigned to investigate a string of murders in Edinburgh that seem connected. Their investigation leads them to uncover a secret criminal organization called Crypt, led by Bismarck Laqueesha, that is planning attacks across the city. As Crypt begins disabling communications and launching assaults, Lowbow and Elmo go on a hunt through the chaos of Edinburgh to find Laqueesha and stop his plans, culminating in a final showdown where Lowbow confronts Laqueesha and discovers Elmo was secretly working for him all along.