Death waits beneath the waves as two estranged lovers face their demons...

Sergeant Nix Marr left her dark past buried beneath the sea. Then Kessandra, the people’s favourite princess (and Nix's much-loathed ex), recruits Nix for a covert mission. Their goal – to investigate a massacre in the under-water city of Fall. Nix tries to refuse, but finds herself boarding a luxurious submersible as Kessandra's bodyguard. After all, Kess always gets what she wants.

As they descend to the city, Kessandra reveals the chilling truth. They aren’t investigating a massacre, but the trigger that caused it – a sickness that turns victims into mindless killers. And when a royal passenger is murdered, it’s clear the infection is on board . . . and no one on the submersible is safe.

Trusting Kessandra, despite her lies, will become Nix's only hope.