Turtles of Grayskull #4

'THE MASTERMIND IS REVEALED! In the wild conclusion to this wicked series, we discover who has been tying the threads of the He-Man and Teenage Mutant Ninja Turtles universes together. He-Man and the Teenage Mutant Ninja Turtles find themselves facing-off against unthinkable mutations and chaos-but this time there's no reboots, no safety net, and no rules! Can our teenaged heroes prevail? � Script by the critically acclaimed and New York Times bestselling writer Tim Seeley. � Four issue series.'