A nuclear submarine. A dead body. A bereaved detective. Something murky lies below in this exceptionally rivetting BBC police procedural. Suranne Jones, Martin Compston, Paterson Joseph and Adam Jones star.   “Suranne Jones feels the pressure in sharp submarine thriller… a dense, sharply written, absolute treat of a show. ★★★★★” – Guardian When a crew member is found dead on the Trident nuclear submarine HMS Vigil, police detective Amy Silva must go aboard to investigate, as the nuclear deterrent cannot be stopped for fear of compromising its secrecy. While the crew write off the death as an accidental overdose, Silva’s questioning raises suspicions of foul play and causes them to close ranks around a secret.