After the catastrophe, people inhabit underwater cities, but the seas have long belonged to the merfolk, and they are not willing to cede their territories. The confrontation escalates into a dangerous conflict, where any wrong move could lead to war. Against this backdrop, the heroine, serving as the personal guard of one of the Primordials, receives an important assignment. Together with Fortis, she is tasked with uncovering the secret of the city of Tau.
Inside — an underwater world of the future, political tension, a clash of interests, and a story of a forced alliance. The partners have to work side by side, although initially there is no trust between them. Gradually, the focus shifts not only to the shared mission but also to a feeling that does not fit the rules of a world divided by fear and prejudice.