Alexandrite mystèrieux de voleur

The prey we are aiming for is neither a diamond ring nor a national treasure masterpiece! I will come for your "most important things".

Paris in the late 19th century. Alexandrite, an unidentified phantom thief who appeared to mock the world of decadence. From green to red, jewels of mysterious varieties, it confuses Paris at the end of the century!

(Source: Bunkasha, translated)