The timeline of this book occurs after the events of In the Shadow of a Dream and before the events of In the Shadow of an Obsession. It does contain spoilers of the first three books in the series.
Possible Triggers:
A married couple struggling with staying together
Abuse
Grooming
Off pages insinuation of incest
Memory Loss and subsequent trauma associated (i.e., panic, agitation)
Grief
Trauma of loss of agency (being drugged - off page)