When the Teenage Mutant Ninja Turtles came across Krang and Shredder making a deal with some otherworldly ''demon-mage'' named Skeletor, things got hella-weird and they ended up in ETERNIA! It turns out, when you mix Utrom mutagen with demon magic you get a nasty purple poison - and it''s brought Eternia to the brink of chaos. So, Leonardo, Raphael, Donatello, and Michelangelo are teaming up with The Masters of the Universe to kick some blue boney butt. The only problem is... He-Man is missing in action. In this thrilling adventure, the Ninja Turtles and He-Man will find themselves pulled together across timelines and cosmos, again and again. A stolen time-scepter causing knots in the universe will cause irreparable damage to all existence unless the Ninja Turtles and He-Man - with the help of apprentice Timestress Renet Tilley - can find and defeat the mysterious force behind all this mayhem. New York Times bestselling author Tim Seeley and Eisner-Award winning illustrator Freddie E. Williams II join forces to bring fans this awesome and long-awaited crossover. Collects Masters of the Universe/Teenage Mutant Ninja Turtles: Turtles of Grayskull #1 - #4.