This Gilded Abyss by Rebecca Thorne (Paperback)

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 underwater city of Fall. Nix refuses, but still 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 is safe. Soon trusting Kessandra, despite her lies, will become Nix’s only hope.