In the pilot episode of Star Vs. The Forces Of Evil Star Butterfly, a teenage adventurous princess gets given a magic wand for her fourteenth birthday. She can't handle the wands power so she gets sent to Earth to train. 

When she gets to Earth she goes to a high school. The principal has a boy named Marco Diaz show her around. He is called the Safe Kid for many reasons. He shows her around but when she shows him the power of her wand he runs away screaming.

Marcos parents take in Star as a foreign exchange student Marco hates her. He runs away from home and goes to the nearest store. They won't let him inside though because he is drenched from head to toe because of a storm cloud Star had summoned with her wand.

Star soon finds him and tries to convince him to come home but behind her an army of villains appears trying to steal her wand and kidnap her. She and Marco take on the villains using karate and the magic wand. 

They bond over fighting the enemies and after one final Narwhal blast the enemies retreat. Marco and Star walk home as the episode ends.