Henry Herbert, ex-police officer and ex-teacher, has started his Private Investigator business in Perth, Western Australia. His first client, a previous mentor. Accused of murder.

Police have arrested a teacher, Henry's mentor, for killing a parent. The teacher admits their meeting got heated, swears he left the room to get coffee, returning to find the parent pushed over a balcony. It leaves a five-minute window where anything could have happened. Except, nobody claims to have heard or seen a thing, even with an event nearby.

To help the teacher's lawyers gather information, Henry returns to a world he thought he'd left behind, going undercover as a substitute teacher. And it's not long before he discovers there's much more happening at his mentor's school, everyone hiding their own secret.

Except Henry's no stranger to secrets. Broken marriages, misused money, manipulation... Henry is already cleaning up the aftermath of his own family's wickedness, with a long-lost half-sister he yearns to find.

As the media portrays tension between teachers and parents, Henry must draw on the parallels between his life and the case to seek the truth and expose the lies. It's the difference between proving his mentor innocent or guilty.