Ninja Go! is a song from the first episode, Darkness Shall Rise.
Ninja, go. Go, go. Where never gonna stop. No, nobody's gonna slow us down. Here we go, go. Shake it up with me. Go, go. Take it to the top. No, nobody's gonna stop us now. We go round and round and round. Get up. Get your ninja on. Spin around and sing along. Gotta Spinjitzu attitude. I'm all right. I've got something to prove. Go, go. Everybody with me. Go, go. Never gonna stop. No, nobody's gonna slow us down.