Mermista, who supports the Great Rebellion, tells Adora that the rest of her people won't fight the Horde because the Horde has never provoked them. But that changes when Hordak steals the Power Pearl that gives Mermista's people their magic powers. She-Ra and Mermista have to retrieve the Pearl before Shadow Weaver learns how to unlock its magic. They get some help from a baby horn whale that they helped rescue from Hordak's troopers. (thetvdb.com)