London Rules might not be written down, but everyone knows rule one. Cover your arse. Regent's Park's First Desk, Claude Whelan, is learning this the hard way. Tasked with protecting a beleaguered prime minister, he's facing attack from all directions himself: from the showboating MP who orchestrated the Brexit vote, and now has his sights set on Number Ten; from the showboat's wife, a tabloid columnist, who's crucifying Whelan in print; and especially from his own deputy, Lady Di Taverner, who's alert for Claude's every stumble. Meanwhile, the country's being rocked by an apparently random string of terror attacks, and someone's trying to kill Roddy Ho. Over at Slough House, the crew are struggling with personal problems: repressed grief, various addictions, retail paralysis, and the nagging suspicion that their newest colleague is a psychopath. But collectively, they're about to rediscover their greatest strength - that of making a bad situation much, much worse. It's a good job Jackson Lamb knows the rules. Because those things aren't going to break themselves.