While there isn't a specific "Case 0," the series officially begins with the first installment released in 2022. The books published in this series include:

The series is known for its blend of historical detail and lighthearted "cosy crime" elements, reimagining the iconic Empress as a proactive figure rather than just a tragic historical icon.

Sisis Gift aus Griechenland Kaiserin Elisabeths vierter Fall

The series (Empress Elisabeth Investigates) is a historical mystery series by Austrian author Thomas Brezina, featuring Empress "Sisi" as a clever detective in the 19th-century Viennese court.

(Case 3, 2023): A mystery involving art and secrets within the imperial family.