Slow Horses season two, episode four, "Cicada," focuses on the "Cicada Program," a Soviet-era sleeper agent plot, as the team confronts Russian adversaries in London. Reddit users highlight the episode's tense, action-driven narrative, noting significant character development for Louisa Guy and tactical displays by Catherine Standish. For a detailed fan discussion of this episode, visit Reddit's r/SlowHorses . Cicada Program | Slow Horses Wiki | Fandom