The Death of a Composer: Rosa, a Horse Drama (1999)

"Rosa", with a libretto by Peter Greenaway and score by Louis Andriessen, is the first in a projected series of 10 operas, each dealing with the death of a famous composer - some real, others fictional. "Rosa" falls into the latter category; it tells the story of Juan Manuel de Rosa, a Brazilian who went to study music in America but spent most of his time in the cinema instead, becoming particularly entranced by Westerns. Now 32 years old and residing in an abandoned Uruguayan slaughterhouse, Rosa has become one of Hollywood's foremost composers, specialising in Westerns. He also has a beautiful 19-year-old fiancee, Esmeralda, but he pays her little heed, instead lavishing his attentions on a black mare named Bola. One day, a group of men attired as cowboys arrive at the abattoir and kill both Rosa and Bola; an investigation is conducted, with particular suspicion!

Unfortunately the movie The Death of a Composer: Rosa, a Horse Drama is not yet available on HBO Max.