London's MI5 agents-in-disgrace end up at Slough House for the rest of their careers, unless they can redeem themselves somehow. It's not easy when they aren't trusted with anything important. Dubbed "slow horses" as slang for their workplace location, their biggest problem is working together cohesively, since they all have their own agenda because of their demotions. Aged, irritable Jackson Lamb, a legend during the Cold War era, is now head of the slow horses. Even though the Cold War is history, it doesn't mean the undercover operatives aren't still working schemes.

When an elderly spy and comrade from that era is found murdered, leaving a cryptic message behind for Jackson, he's sure there's a connection to an upcoming MI5 summit with Russian oil billionaire Arkady Pashkin. Jackson is convinced the meeting has less to do with an oil deal than the promise of future political alliances. Pashkin and his cohorts seem like nothing more than rich Russian gangsters. Using all the knowledge and resources in his firm of disgraced agents, Jackson starts digging and what he discovers is bizarre. Things are not quite what they seem as some unsavory Kremlin ghosts from the past start making untimely appearances. But will the outcome help or hinder Jackson and his slow horses?

DEAD LIONS by Mick Herron is a labyrinth of tricky twists and turns as the intense investigation progresses to its ultimate resolution. Jackson and his MI5 agents at London's Slough House are a motley crew, indeed, but they are eventually able to come together for the good of the nation, though it does seem quite doubtful at times. That's what makes DEAD LIONS such interesting, hypnotic crime fiction.