Few books keep me up past my bedtime, but Harry Bingham's The Strange Death of Fiona Griffiths did. Way beyond, actually.
In the third book in the Fiona Griffiths series, Cardiff, Wales, Detective Constable Fiona Griffiths goes undercover.
After the brutal murder of a software specialist who has been planting malware on corporate computers, police start investigating.
Meanwhile, Fiona is one of the few graduates of the hard-assed police school for undercover agents. (The author assures us in an Afterword that this school does exist.)
When Fiona finds another woman who died a horrible death as the result of the scam, police decide to plant Fiona in a compromised corporation. As a payroll clerk, she will see how the scam works. Maybe she will find its source.
Police can easily catch the underlings. Finding the person who has funded the plan is almost impossible. You can shut down the operation for a while, but it comes back in a slightly different form somewhere else.
So Fiona risks her life, goes undercover, and finds herself in the same place as the head honcho himself, but she never sees him. She does learn that when the whole scam is put in operation, it will steal hundreds of millions of pounds and probably bankrupt huge corporations.
Also, if the malware ring senses they are about to be caught, they can activate a software program to clean out the payroll accounts and immediately bankrupt many of the corporations.
So there is much at stake. But it doesn't end there. The crime ring kidnaps another undercover agent put in place to direct attention from Fiona. This man has a young wife and small children.
Fiona continues to try to find out about her own identity. She is the adopted child of a former local mob boss.
She continues her love affair with a fellow cop.
Fiona begins to like her assumed identity more than she likes herself. She does, after all, have a major mental illness the symptoms of which still come and go.
There is much more in this book, but I've probably told you too much already. The book ends with Fiona acting desperately. By the end of the book, she makes a life-changing decision, one of special interest to readers' of the series.
The Fiona Griffiths books are a continuing story. If you have not read the series but think you might like to, the first book is Talking to the Dead.
I very much enjoy the Fiona Griffiths books. No doubt, there are (or soon will be) more of them to make me put off my bedtime.