When Australian Intelligence Officer Michael Cooper's dismembered body is found in a suitcase at Brisbane Airport, Detective Sergeant Tilly Johnson is pulled into a dangerous world of international espionage. As she digs deeper, she uncovers a Russian spy network—the Shadow Syndicate—that has infiltrated the highest levels of Australian institutions.

Teaming up with her resourceful partner, Detective Jimmy Nguyen, and the elusive hacker BrissieByte, Tilly embarks on a high-stakes mission to expose the Syndicate's deadly plot. From Brisbane's tech underworld to intense face-offs with ruthless Russian operatives, Tilly and her team must navigate a web of lies, betrayal, and shifting allegiances.

With the threat looming, Tilly is forced to question everything she stands for, pushing the limits of the law and risking her career in pursuit of justice. As the clock ticks down, she confronts not only the powerful forces behind the Syndicate but also her own inner struggles, knowing that stopping them may come at an unbearable personal cost.

Set against the sweltering streets of Brisbane, Under the Code is a gritty, fast-paced thriller that delves into the complexities of loyalty, sacrifice, and the blurred lines between right and wrong in an age of digital warfare.