In 1950s Boston, the best way to survive is keep your head down and your mouth shut. But Cal and Dante prefer to do the right thing, not the sensible one.

When a body is discovered tarred, feathered and shot, it is dismissed as a gangland killing. But Cal O'Brien's cousin, detective Owen Lackey, recognises the murder as the typical retribution for IRA informers.

Owen knows that no one in the tight-knit Boston Irish community will talk. He turns to Cal and Dante for help, sending them into the city's shadowy underbelly. But there's a war on its way - and they're walking straight into the middle of it.