The Serpent Under Treachery, Twists and Terror in Baker Street

The Serpent Under by Bonnie MacBird is, as far as we know, the latest instalment in her Holmesian series — and although it isn’t officially the finale, it feels like one for now. I’m utterly devastated at the thought that this might be the last, and I sincerely hope she continues writing, because the series has finally reached its full potential. Anyone who has read my earlier reviews knows I did not love the beginning of this series. I struggled with the first books: they were out of tone, uneven, and at times downright frustrating. I said so openly. But somewhere around the midpoint, everything changed. The writing sharpened, the characterisation deepened, and the stories began to align beautifully with the Holmesian spirit. From that turning point onward, each book grew stronger — and The Serpent Under is the crown jewel. MacBird is not Conan Doyle — no one is — but here she is at her absolute best. The pacing is tight, the atmosphere rich, and the mystery compelling right to the final page. It’s intriguing, elegant, and wonderfully constructed. Holmes and Watson are portrayed with authenticity and respect, their voices and dynamic finally matching the tone I had been longing for since book one. This isn’t just a pleasant read. It’s marvellous — clever, immersive, and deeply satisfying. If this is the last book for now, it’s a beautiful high point. But I truly hope it isn’t the end. I’m absolutely not ready to say goodbye.