Souvenir centers on the musical career of Florence Foster Jenkins, a wealthy woman with a striking lack of talent. In 1932 she met mediocre pianist Cosme McMoon and the two teamed up in the hope of achieving success in the music world. Over the next 12 years, their bizarre musical partnership earned them extraordinary cultish fame, and their awkward pairing evolved into a friendship as full of light and warmth as the spotlight they shared, culminating in a sold-out performance at Carnegie Hall.