When a supernatural object explodes, it gives Marco strange abilities that change his life. When the strange trans-universal mercenaries known as Arch Angel recruit him, he faces something deadlier than monsters and demons. But can he face the reality of something bigger and more powerful than Star's magic that lives inside of him?

Marco Diaz is just your average 15 year old high school student. That was until his parents tells him that their family were protectors of Mewni, and he was tasked to go under the request of the royal family. How will Marco adapt to living in a world of magic. What foes and challenges will he have to conquer, and how will he become the famous "Red Knight of Mewni."