Cunnell's 2008 debut Marine Boy was an arresting coming-of-age novel, set in a vividly rendered 1970s Eastbourne. It introduced Kim, a fatherless boy who lives for the summer and the sea, but is dragged into deep waters by his love for a skinhead girl. The Sea on Fire opens with Kim as a married father, living in Brixton, but still unable to settle. When his old diving partner asks him to join a private cruise in the Red Sea, Kim cannot resist. But the moment he sets foot on gangster Teddy King's yacht, old troubles resurface. Aboard a floating den of narcotics, Teddy and his young companion, Jody, stir up disconcerting echoes of Kim's past and a dark undertow of conflicting loyalties and desire pulls Kim into actions with dangerous consequences. Cunnell maps new noir territory in an incandescent underwater world, where shipwrecks and luminous sharks are described as precisely as the madness and weakness in the hearts of men, the slipperiness of relationships and identity, with a quest to find what really lies beneath.