Which Witch is the third and final book in Simon Green’s Holy Terrors trilogy, following the odd-couple investigative team of Alistair Kincaid, a bishop from All Souls Hollow, and Diana Hunt, an actress with a flair for the dramatic. In true series fashion, they’re back solving another mystery tinged with the paranormal—and this time, the spotlight is on a cursed production of Macbeth.

Diana is working with a struggling theater company rehearsing the famously unlucky play in a rundown venue. But when a prop cauldron releases actual poisonous gas, things take a dangerous turn. Diana calls in Alistair to get to the bottom of it, and the investigation quickly spirals into murder, magic, and dark secrets. Witchcraft or black magic seems to be the obvious explanation, but Alistair is convinced there’s a human hand behind the horror.

This was my first foray into the Holy Terrors series, and while I occasionally felt I was missing some background, the book stands well enough on its own. Green’s writing is descriptive and atmospheric without being overwrought—you can practically feel the grime of the theater and the creeping unease in its shadowy wings. The dialogue-driven style gives readers a chance to do some sleuthing of their own, which I appreciated.

Where the book faltered a bit for me was in the character development. Alistair felt rather cold and distant, and Diana leaned heavily into the “diva” persona. If there was meant to be romantic tension, it never really landed—though to be fair, the focus is clearly on mystery over romance. Still, a bit more warmth between the leads might have helped deepen the story’s emotional stakes.

Despite that, the plot kept me guessing, and while I had theories by the end, I wasn’t entirely right, which is exactly what I want from a mystery. All in all, Which Witch was a fun and engaging read, and it’s made me curious enough to want to read the first two books. That, in itself, is a strong endorsement.