Under the Pampas Moon: Cesare Campo is a hard-riding and hard-loving Argentine gaucho. Yvonne LaMarr is a famous Parisian singer on her way to play an engagement in a Buenos Aires cabaret. THe plane she is flying in is forced to land on the Pampas. Campo and his riders take the passengers to a hotel. Yvonne and Campo quickly fall in love, but she had to leave to make her singing engagement in Buenos Aires. Campo follows her and discovers that his horse that was the favorite to win the Big Race has been stolen.