Main •
Luke Roberts as Eric Beaumont, an experienced crisis and hostage negotiator. He grew up in
Chicago, where his mother, a surgeon, still lives. •
Nazneen Contractor as Zara Hallam, the team's lead investigator •
Brandon Jay McLaren as Oliver Yates, a psychological profiler •
Sarah Greene as Maxine Carlson (season 1–2), a crisis and hostage negotiator who acts as Beaumont's
second. She takes leave from the team during the second season after being forced to use lethal force against a perpetrator to save Oliver. •
Karen LeBlanc as Cynthia Walker (season 2–3), a crisis and hostage negotiator who works with Eric on a case during the second season, and eventually joins the team as Maxine's replacement as Beaumont's new
second-in-command.
Recurring •
Emma de Caunes as Nathalie Denard, Eric's ex-wife and the CEO of an insurance company •
Carlo Rota as Damian Delaine, an enemy from Eric Beaumont's past •
Natalie Brown as Kate Barrett (season 3), an FBI agent and Eric's girlfriend •
Emmanuel Kabongo as Tyler LeFebure (season 3) ==Filming==