One hot summer's day, an old flame turns up at Lafferton HQ and Simon Serrailler is catapulted back to his days as a fresh-faced PC in the Met.

That long febrile summer in the early 1990s, London was reeling from one IRA bomb warning after another. Sirens. Blue lights. Tyres screaming. People running. The army called in. And Simon in the thick of it. Until he's pulled aside and put on a very different kind of job: his first undercover op awaits. Will the young Simon be able to hold his nerve? Or is he walking into a trap?