In the dimly lit rooms of Braun's house in Budapest, Marie grapples with shocking family secrets revealed in a letter from her late mother - a woman she knew as her beloved aunt. The letter stitches together tales of forbidden love, an unexpected lineage with the great composer, Ludwig Van Beethoven, and ends with an urgent request - protect the truth of his secret love affair, detailed in the lost letters to the Immortal Beloved; letters the world has never seen. With newfound purpose, Marie prepares to delve deep into Budapest's enigmatic past to find the lost letters, unraveling mysteries that will invariably transform her life. Trusting in Braun and her mother's confidants, Marie risks her life to protect the extraordinary family legacy she's only begun to comprehend.