Well, first: it's very long, 647 pages in hardcover.
It's number four in "Robert Galbraith's" series of novels centering around ace British detective Cormoran Strike and his plucky assistant Robin Ellacott. And you really should read them in order. Because…
This one opens pretty much where book three left off: Robin's wedding, at which Strike has unexpectedly shown up,(unintentionally) wrecking the newlyweds' happy day. Will Robin and her hubby recover marital bliss from this setback? No spoilers here.
A year later, and Strike is intrigued by Billy, a troubled young man who shows up at his office babbling incoherently about a long ago murder, then runs off without further details. Intrigued, Strike's (unpaid) investigation leads him to Jasper Chiswell, a Tory cabinet minister who's being blackmailed by Billy's brother. For what? We're not told straight off.
In fact, we're told pretty much nothing straight off. Strike's investigation encompasses many, many colorful (and mostly unpleasant) characters from Chiswell's family and acquaintances, who have a long history of (mostly) sordid behavior. And it's not until page 281 that an actual dead body shows up. Seems to be an "obvious" suicide, but is it really?
Well, the investigation reveals a lot of complex and dysfunctional relationships. It was (frankly) difficult for me to keep track of all the characters and their past and present doings. Britishisms kept popping up in the text, some of which I knew, some of which I figured out via context, and many remained a mystery. Surrounding it all was Strike's and Robin's troubled relationships, with others, and themselves. (There are some rom-com notes here.)
And did I mention it's really long? And it's getting worse: Amazon says book number five is 944 pages, book six is 1024 pages. Should I keep going? The sunk-cost fallacy says yes!