It’s early summer in Algonquin Bay and the blackflies aren’t the only ones out for blood. Detectives John Cardinal and Lise Delorme find themselves with a strange case on their hands involving a young woman with a gunshot wound to the head. The investigation quickly takes a turn as Cardinal and Delorme uncover a series of disturbing, ritualistic killings that may be connected to their young victim.

As Detective John Cardinal and Lise Delorme’s investigation into Algonquin Bay’s most gruesome double murder brings them precariously close to a doomsday cult with nothing to lose, Cardinal launches his own investigation into a case far more personal and dangerous. With doubts about Catherine’s suicide swirling beneath Cardinal’s placid exterior, Delorme stretched thin in her role as lead investigator on an increasingly complex, and far-reaching case, the pursuit of the killers will push them both to the breaking point. Delorme must decide whether she can trust Cardinal, or whether the death of his wife has sent him into a delusional state that puts the entire case at risk.

Detectives John Cardinal and Lise Delorme have grown closer as friends and partners. There’s a strong bond between them that transcends the job, a bond that deepens all the time and yet remains largely unspoken. But when a seemingly mundane missing persons case turns into a spree of nightmarish murders, the ensuing investigation pushes them to their limits as detectives and partners, forcing them each to face what their future holds.