From Netflix:
Martin and Claudia, top-flight lawyers who happen to be former lovers, become targets when they’re teamed up to defend a notorious terrorist. As the trial unfolds, the danger causes the pair to reevaluate their allegiance to justice.
If the plot confuses you in any way, you can read the Wikipedia summary. Nothing special distinguishes this story from other cloak and dagger films. MI5 is painted as a ruthless organization not above murdering their agents in order to cover up MI5 mistakes. But then clandestine government organizations are never suspect, are they? (Parlez-vous CIA?)
Eric Bana as Martin Rose and Rebecca Hall as Claudia Simmons-Howe play well as a team. Other notable appearances are from Ciarán Hinds as Devlin and Jim Broadbent as Attorney General.
Try the British TV series “MI5” instead.