One of the last movies of Julian Sands prior to his disappearance on January 13, 2023, when he was hiking close to the Mount Baldy area of California's San Bernardino Mountains. A search and rescue expedition was unsuccessfully launched to find him, his corpse being found by chance five months later at Mount Baldy. The movie is dedicated to him with the line "To our master, Julian" before the end credits.
Melanie tells Gustafson that Katherine composed the original concerto when living in Hannover, Germany. The city of Hannover is less than 20 miles from Hamelin, whose story of the Pied Piper is recreated in the film, and the whole district is notorious for its tales of the supernatural, even being used for pagan rituals during the Nazi regime.
In the original story of the Pied Piper of Hamelin, which the film re-imagines, the Piper took the children of the townspeople after being refused payment for getting rid of the village rats, leading them to the woods where they forever disappeared. Coincidentally, actor Julian Sands, who plays Gustafson and to whom this film is dedicated too, died tragically after disappearing in the woods in January 2023, his remains only being found six months later.