What should have been a simple pick-up turns into a day-long nightmare for Bad Sam Chapman.

When an operational catastrophe puts a gun in the hands of a young man, who then breaks into South Oxford Nursery School and takes a group of hostages, teacher Louise Kennedy fears the worst. But Jaime Segura isn't there on a homicidal mission, and he's just as scared as those whose lives he holds as collateral.

As an armed police presence builds outside the school's gates, Bad Sam Chapman - head of the intelligence service's internal security force, the Dogs - battles the clock to find out what Jaime is after. But the only person Jaime will talk to is Ben Whistler, an MI6 accountant who worked with Jaime's lover, Miro.

Miro's gone missing, along with a quarter of a billion pounds allotted for reconstruction work in Iraq. Jaime refuses to believe that Miro is a thief - though he's always had his secrets. But then, so does Louise, so do the other hostages - and so do some people on the outside, who'd much rather Jaime was silenced.