If Dubliners in 1916 weren’t having it rough enough what with rebels fighting in the street and gunboats on the river, there’s a killer at work in the red-light district in the northeast of the city immortalised as Joyce's Nighttown. The murderous man grew from a boy who might have been called Charley Moore and was raised in the harshness of Alaska by a father who wasn't above killing innocent if naive passers-by so that his family might survive. Christopher Flinter, meanwhile, a trench deserter, is saved from a firing squad by Major Byatt in the castle after being picked up whilst seeking revenge for his dead brother and fighting with members of the DMP. In another part of town a 'clergyman' takes the life of a young newspaper employee Daniel Joyce.

To put all this together, Flinter - given the choice that's no choice at all of working undercover or taking a bullet - is set on the hunt after Janus, this vicious killer who also works a sideline as a German agent who helped put the Lusitania at the bottom of the ocean, murdered the major’s close friend, and has now set upon the working denizens of the Monto.

Byatt - a good chap and a friend of Dorothy at a time when that was deemed socially and legally unacceptable - buys the younger man some decent clothes and a feed before Flinter, now Joseph Andrews thanks to some fake papers, checks into a Talbot Street hotel and begins his pursuit of the “nameless shape that lurks in the shadows” through a city set on edge by General Maxwell’s ill-advised executions of the rebel leaders. He’s aided in the search - and taken into bed - by love-interest Nell, who’s got a backstory of her own, and music-loving pub-owner Shanahan who first threatens our hero with a gun before doing him a proper fry-up.

Tight of plot, sharp of dialogue, and gripping as a vice, O’Reilly’s debut novel – based in part on his grandfather who signed up with the British army to escape slum life – is a cast-iron cracker. He brings the period alive and manages to incorporate knocking shops, shocking poverty, the Rising, the Magdalene Laundries, gay Dublin, and the Great War into the action while creating a thoroughly modern murderer in the stock trading, secret agenting, multiple-alias having malicious not-loyal-to-any-flag man of the future at the yarn's centre. Take yourself up to Monto.