Michael has been a busy man since being fired from Tactical Response. Thanks to the squad's head honcho Kerry he's now undercover, and his job is to bring down the Raineys, a family team of cocaine importers. He sets up a buy-bust meeting in order to bring the Raineys down and coaxes Josh into becoming his wingman. The trade-off location changes at the last minute and whilst TR catches some of those responsible. Col Rainey has taken Michael and gone underground. Has his desire to prove himself to everyone put his life in serious danger? Meanwhile, Shannon finds herself face-to-face with her attacker.

Tactical Response goes into overdrive as they desperately try and to locate Michael after his undercover buy-bust goes horribly wrong. Josh starts to crumble under the guilt of letting Michael get away while Stella is furious, realising her best friend, and once lover, may not come back alive. It's a race against time as Kerry fights political red tape and the remaining members of Tactical Response do anything they can to get one of their team back safely.

Tragedy can have a profound effect on those involved. Everyone has different coping mechanisms, and Tactical Response continues to reel from a tragedy within their own ranks. Stella can barely build up strength to face the day and Christian appreciates a comforting presence from Amber. Josh, feeling responsible and immense guilt from what has happened, goes underground, deliberately avoiding contact from anyone at TR.