Chords of Death in A Major

1912. In Angers, during an avant-garde concert, a famous singer dies, and a piano tuner jumps from the Eiffel Tower. Society is agitated. The sounds of a deadly waltz are already echoing across the country, where each chord may become the last. The case is entrusted to Gabriel Lenoir, but the detective suffers from past wounds, and his assistant cannot hear the music…