Onegai shimasu, Leonardo-kun. Raphael-kun?

You should know better than to challenge father.

(dramatically telling a story, very much inflection and variety in her voice) Fifteen years ago, you were all regular turtles, but you were part of lab experiments, which made you into the mutants you are now. You were held in the clutches of the evil Hamato Yoshi, who treated you all like slaves. But father found his secret lair and killed Hamato Yoshi, and saved you all. Now we're all one big happy family.