- Season 6 Episode 21
The Unrivaled Standard
Lt. Severide is shocked when Rene Royce (guest star Sarah Shahi) resurfaces at the firehouse. Casey comes up with a plan to help Chief Boden in his latest pursuit. Kidd regrets a decision she made regarding Severide. Herrmann doesn't see eye-to-eye with Lt. Colannino (guest star Andy John Kalkounos) over coaching their son's basketball team.