In his apartment building in the city, Sam hears all kinds of noises coming from behind closed doors-voices, a dog barking ,a loud TV, snoring, even crunching potato chips. But one rainy day he hears the sad soudes of a harmonica. "Who's that playing?" he wonders. Sam's search leads him th the dark and mysterious APT.3, where he finds not only htesource of the music-but a new friend.