THIS IS WHAT HAPPENED

The latest stand-alone from Herron couldn’t be more different from his bustling, often brutally funny series about the government agents at Slough House (Spook Street, 2017, etc.). This pared-down exercise in suspense is just plain brutal.

“I wish this were like the films,” Harvey Wells tells Maggie Barnes, the mouse he’s recruited to run a delicate undercover errand for MI5. All Harvey wants Maggie to do is install an eavesdropping program in one of the computers in Quilp House, where she works in the bowels of the post office. And it’s for the good of her nation and the world, since the functionaries of Quilp House, it seems, are actually working for the Chinese government. But Harvey can’t offer Maggie moment-by-moment instructions or surveillance or backup; if she gets caught or anything goes wrong, she’s on her own. This opening movement recalls the recruiting of the suicidal heroine of So Many Steps to Death 60 years ago, but Herron has some fantastical twists in mind that Agatha Christie never dreamed of. Something does go wrong; Maggie does get caught; and although Harvey rescues her, her life as she knows it is essentially over. To say more would spoil some of the surprises planted at regular intervals throughout the hyperextended period following Maggie’s single attempt at counterespionage. Suffice it to say that Herron spins a remarkable, if often blankly incredible, tale whose dramatis personae are limited to three characters, one walk-on, and a few others dimly or harshly remembered.

Given Herron’s outrageous premise, the complications are managed with delicious control. Only the last act stumbles, because the climax is the only part of this story that’s remotely predictable.