This is a MIDI of the "Light," the finale of the broadway musical Next to Normal. If you open this in music notation software (Finale, Sibelius, NoteWorthy Composer, etc), then top staff is Natalie, second staff is Diana, third staff is Dan, fourth staff is Gabe, fifth staff is Dr. Madden, sixth staff is Henry, seventh staff is right hand (piano), and eighth staff is left hand (piano). Even though the male parts should be in treble clef an octave down, I had to input them on bass clef so that they'd play in the right octave.