I'll try a longer summary:
Fry is still practicing the holophoner because it impressed Leela, but at a recital he does badly and his teacher tells him he'll never learn. He becomes even more depressed when Leela mentions her old boyfriend Sean was a musician. Bender decides to help by taking Fry to the Robot Devil, who offers to give Fry robot hands that can play. Of course he's planning to trick Fry, but his plan backfires and Fry ends up getting his hands. With the Devil's hands, Fry becomes a virtuoso musician, and writes an opera to show Leela how special she is. Leela is impressed and maybe attracted to him, but it might only be because of his new talent. Meanwhile the Devil plots to get his hands back, and causes Bender to deafen Leela. During the performance of the opera, Leela is so desperate to hear it that she makes a deal with the Devil to hear again, but it turns out she has to marry him in return. Fry and the Devil argue during a long musical sequence, but finally Fry gives back the hands to save Leela. Afterward, Fry can't play anymore and everyone apparently leaves the auditorium. Depressed again, Fry starts to leave, but Leela tells him she wants to hear how it ends; the rest of the building is empty but she's still there, even though he's lost his talent. Fry picks up the holophoner and plays, making crude images of he and Leela appear. They take hands, kiss, and walk away, always looking into each other's eyes, and leaving us to assume that's how things really end between them.
Oh, wait. Here's a transcript: http://www.leelazone.com.ar/scripts/4acv18.shtml