The Argentinean pianist Miguel Angel Estrella was arrested in Montevideo during Operation Condor in December 1977. Accused of being a member of the Montoneros, a Peronist guerilla movement, he was tortured and held incommunicado before being transferred to Libertad, where political prisoners from Uruguay were assembled. Thanks to an intensive and international solidarity campaign, launched by his friends in Paris and led by classical music celebrities as well as diplomats, human rights activists, and a myriad of anonymous music-lovers, Estrella was released and expelled to France in February 1980. Drawing on archival materials from the Estrella support committee, diplomatic files, interviews, and recently declassified documents from the Uruguayan military court, this article retraces the construction of an exceptional “cause,” shedding new light on the relations between music and diplomacy during the Cold War. It examines the musician’s experience in prison, where he painfully managed to play Beethoven sonatas on a silent piano, as if mirroring the media’s portrayal of him as a Beethovian hero, a sort of modern Florestan. It also analyzes the connections between ethics and aesthetics, and the role of emotions in international political mobilizations.