With Tess now back on duty as a police consultant, and Sunny as her under the radar tech partner, a close to home murder of one of Matt's colleagues challenges the duo on their first ‘on the books' case in the pool where Tess swims. As they investigate the mystery surrounding the swim coach's death, and the dynamics of her Olympic-level swim team, Tess and Sunny discover they were on opposite ends of the popularity scale in school. Mia offers her unexpected skills to the case and a shaken Matt sees a new side of Tess. Meanwhile, Sunny is desperate for help with a DIY job gone awry and lets her concierge, Kye, into her apartment, reawakening past trauma.