When Ernst Grip of the Swedish security police, lands at a remote military base in the Indian Ocean, his escort, FBI agent Shauna Friedman, asks him to determine whether a prisoner is a Swedish citizen. At the military base, the prisoner, known only as N., refuses to talk. It appears he was involved in an Islamist-inspired terror attack in Topeka, Kansas. The attack was real, but the motivations behind it are not so simple.