Eggman has been done away with by a new villan, Black Heart. But Eggman isn't the only victim of this tyrant. Amy, Shadow, Knuckles, Rouge, and many others have been savagely murdered, thanks to the help of Black Hearts ability to use sorcery. The only two left are Sonic and Tails. Their only hope of defeating Black Heart, is in a human girl of the age of 18 named Caliope. They bring her into the world of Mobius, and transform her into a Mobian hedgehog so she can defend herself. Together, the three set out to save Mobius, again. Can they stop Black Heart, before he kills them too?
i would have to rate it maybe PG13. It contains violence, gore, and mature scenes.