Soon after the cargo liner Alexandra Rose steams into the Mersey Estuary, one of the ship's passengers is found dead, leading into Detective Inspector Andy Ross's most baffling case to date.

Another death soon follows, and Ross discovers that the case has its roots in the depths of the Amazon Rainforest. A billionaire entrepreneur, mysterious passengers, a team of researchers and a band of vicious mercenaries all have their part to play.

Working the case, Ross and his team from the Merseyside Police Specialist Murder Investigation team will need all their skills and resolve. But can they solve the mystery of the Mersey Mariner?