
The anime short starts off with a lonely, sad ghost girl, who happens to hear two haunted tap shoes singing and dancing to “Moses Supposes” from “Singing in the Rain.”

She’s hesitant at first, but soon she starts trying to dance with them, and as the song goes on she breaks into a tap-dance routine just like Gene Kelly’s. It’s kind of bittersweet, as the shoes lose their movement, but in the closing we see a shopkeeper (Named Mose!) watching the ghost girl looking at a sign in his window for “Singing in the Rain”, and the last scene shows them in a theater where she’s enjoying “Singing in the Rain” with the shopkeeper!
(Update: I didn’t know this before but the other singer and dancer you hear is Donald O’Conner!)