The annual Rap Battle in the Park is just around the corner and the Ninjas naturally sign up. Maurice is confident that he and his friends will take first place again this year, even though the T-Rex crew is among the tough competition. But Maurice's voice suddenly causes problems and Mau croaks like a raven. What at first sounds like a cold later turns out to be a serious problem, because Maurice's voice has suddenly changed. Max also has his problems with low and high voices, as he learns how to adapt the piano accompaniment to different voice pitches using the song "Heidenröslein" by Franz Schubert.
The annual Rap Battle in the Park is just around the corner and the Ninjas naturally sign up. Maurice is confident that he and his friends will take first place again this year, even though the T-Rex crew is among the tough competition. But Maurice's voice suddenly causes problems and Mau croaks like a raven. What at first sounds like a cold later turns out to be a serious problem, because Maurice's voice has suddenly changed. Max also has his problems with low and high voices, as he learns how to adapt the piano accompaniment to different voice pitches using the song "Heidenröslein" by Franz Schubert.