Islamic State is here, all around us.
On the Syria/Iraq border, a British hostage is beheaded by IS terrorists. A mysterious figure rules with terror and an iron-fist. They call him the Caliph. In Nigeria the British Ambassador and his young aide are kidnapped. A four-person SAS team is deployed to find him, including Danny Black and Caitlin Wallace. There they uncover an IS plot to unleash a bio-terrorist attack. Time is running out and the team must prevent the deadly disease from being released much closer to home.