Actually, there are more than two missing persons. A third is Steele's unofficial/unauthorised informant Steve Polmont, gone missing working undercover on one of Malk the Knife's building sites.
As if that's not enough to be going on with, MacBride throws in counterfeit goods, fake banknotes, raids on jewellery shops involving sawn-off sledgehammers, a group of heavies from somewhere or other lurking on the periphery and a lawyer alleging malpractice in the interrogation department after a vindictive DI Beattie has doctored the documentation.
In other words there's plenty there to keep McRae hopping.
Enough, in fact, to have him hitting the bottle to the point where goth crime scene technician girlfriend Samantha is about to call it quits. MacBride handles all this with a deftness that keeps you turning the pages through a fast moving story line with plenty of dark humour and the occasional flatulence-induced belly laugh (and no, they're not all the work of McRae's colleague Biohazard Bob).
Through it all McRae continues to come across as a believable and likeable character who attracts the reader's sympathy as the pressure of his job, along with constant criticism in his personal and professional life produce an entirely understandable attitude problem.
When DI Beattie comes unstuck through his own incompetence I found myself hoping McRae would be getting a well-deserved promotion, though at the same time one hopes he doesn't since that would make DI Steele his equal rather than his superior, a situation that wouldn't have the same je ne sais quoi as the current set of circumstances