Klára has been a relationship coach for many years, during which time she has helped countless satisfied clients and is renowned as the best in the business. David is a successful marketing director at an established company, but his love life is at a standstill. Ever since his marriage was destroyed by a relationship coach, he can't stand any coaches like that. But fate had other plans. Klára and David meet and immediately hit it off. Everything goes well until Klára confesses her real job to David.

Genetically modified bull sharks attack Prague's waterways. Detective Kowalski, Dr. Novak, and Dr. Cerny uncover that Dr. Reef is responsible, seeking to weaponize marine life. They work together to infiltrate his lab, outsmart his defenses, and confront the threat.