Summary: At the height of the War of Independence, Michael Collins’ squad member Jimmy Mahon is given an intelligence role while Ursula Sweeney, a code-breaker with British intelligence at Dublin Castle, contemplates treason.

Summary: General Winter targets Sinn Féin’s propaganda machine and their finances, while Jimmy puts pressure on Ursula to feed him information.

Summary: Jimmy breaks Joey out of prison, and helps Ursula to be reunited with her son. Eithne's outrage at Diarmuid's death is ignored, and Maurice faces an impossible choice.

Summary: General Winter suspects Lily of being a spy, and Ursula must try to help her without implicating herself. Robbie plans to kill Eithne, but is stopped by an unexpected opportunity.

Summary: In the aftermath of the multiple attacks on General Winter’s spy ring, the British close ranks. There’s a price on Ursula’s head and Jimmy finally confronts the mole inside Collins’ Squad. General Winter commissions Major Mills to take men to Croke Park.