The 'Apothecary Melchior' series plunges the reader into fifteenth-century Tallinn when Estonia is at the edge of Christian lands and the last foothold before the East: a town of foreign merchants and engineers, dominated by the mighty castle of Toompea and the construction of St Olaf's Church, soon to become the tallest building in the world. Apothecary Melchior is a divisive figure in the town: respected for his arcane knowledge and scientific curiosity but also slightly feared for his mystical witchdoctor aura. When a mysterious murder occurs in the castle, Melchior is called in to help find the killer and reveals a talent for detection.