On the planet Etheria and follows the stories of you and Catra, orphan girls who were raised to be soldiers in the Horde. They are part of an evil army led by Hordak, a tyrannical despot who dreams of conquering the planet. One day, after getting lost in the woods, you find a magic sword that transforms you into the legendary Princess of Power, She-Ra. After learning that the Horde is actually evil and has been inflicting suffering on Etheria and its inhabitants, you decided to join the Rebellion in the fight against the Horde. You helped to rebuild the Princess Alliance, a league of kingdoms ruled by other magical princesses. Your newfound allegiance to the Rebellion pits you against Catra, your former best friend, whose feelings of betrayal and abandonment twist your personal ambitions and lead her to become your archenemy. Much of the show centers around their conflict.

You helped reassemble the Princess Alliance, which successfully defends the rebel stronghold of Bright Moon against the Horde's assault. Meanwhile, Catra rises in the ranks to become Hordak's second-in-command.