Season 2 of Slow Horses ('Dead Lions') anchored itself in classic John le Carré territory, sparked by the mysterious heart-attack death of Dickie Bow, an aging former undercover operative found dead on an ordinary London double-decker bus.
Jackson Lamb’s suspicion that Bow was murdered uncovers a covert clue left behind: a burner mobile phone taped beneath a passenger seat displaying the draft message 'cicada.' The revelation resurrects an ancient intelligence rumor that Russian KGB spymaster Alexander Popov had planted a network of deep-cover sleeper agents throughout British society decades earlier.
The arc shines because it forces Jackson Lamb to confront the lingering ghosts of his Berlin operational days. As rogue Russian assassin Ilya Chernitsky targets former British assets, Lamb mobilizes Slough House to unravel an impending anti-capitalist attack on a London financial skyscraper. Season 2 established the show’s ability to bridge vintage Soviet espionage mechanics with modern post-Cold War geopolitical anxiety, cementing its status as the premier spy procedural on television.