Events in this volume follow pretty much immediately after those of Blue Monday. There's a brief recap to refresh your memory if you're reading them a year apart as they were published, and again in the next one, but I'd strongly recommend gobbling them all up back-to-back.
Freida Klein is a complicated character. She's amazingly private, but not cold, and other people appreciate her kindness, sensitivity, and good advice. In her orbit there's a sister-in-law and teenaged niece, her mentor, the clinic's manager, a former patient, the friends with the cafe she relies on so heavily for all her meals, the therapist she is mentoring, the Ukrainian builder, the lover who left her for a job in the US, and now various people from Scotland Yard.
She has a strong network, but she's not in the habit of asking others for help. And now, after the successes and failures of the case she helped on, she's having a bad time coping. And then there's another case centered on a woman with profound mental issues.
As mysteries I quite like these books. They're not exploitative of their victims and the bad guys are never one-dimensional. Through Klein the reader is given a deeply empathetic look at the lives of people who've been overlooked, neglected, forgotten. The format of the series means that the reader keeps abreast of events after the police are finished detecting: there's both emotional and legal ramifications to follow up on.
There is also a very sad tone to the books. Klein is an insomniac, prone to walking the streets of London when her mind is restless, but it's not a hopelessness in the face of the horrible things humanity does to itself. Even where it isn't possible to save everyone, or prevent violence, it is possible to help people, and Klein doesn't stop trying. Despite the book's long cold winter, there will be better, warmer, times ahead.