Eclipsa is now the queen of Mewni, after Star willingly ceded the throne. Under her rule, the living conditions of the monsters have greatly improved. However, the Mewmen parts of the kingdom have fallen into disrepair and the people blame the royal family for their situation. Star, River and Marco, meanwhile, have been searching for Moon, but to no avail. They receive a tip that she is at a local "Pie Festival", only for it to turn out to be yet another false lead. However, afterwards they discover that the pies from the festival were made using Moon's recipe, finally giving them a genuine clue.
Star, Marco, and River arrive at the home of the Pie Folk, only to immediately be captured. Fortunately, they are rescued by Foolduke and Ruberiot and continue their search for Moon. They eventually find her, still suffering from amnesia, magically making pies for the Pie Folk. They attempt to escape with her, but are stopped by the Pie King, who reveals Moon and Star's ancestor, Queen Festivia, to have been a Pie, making them half-Pie. Due to her amnesia, Moon initially opts to stay with the Pies, until she regains some of her memories after she and Star sing together. They then flee with the Pies giving chase, not wanting to lose the revenue from Moon's pies. In the end, they all escape by hot air balloon with Foolduke and Ruberiot and Moon promises Star and River that everything will be.
Star, Marco and River return to the monster temple with Moon, who's memory still has not fully returned. Star convinces Marco and Eclipsa to keep her mother in the dark about Globgor, but she eventually discovers him anyway. Contrary to what they were excepting though, Moon claims to understand Eclipsa wanting him back and the two get along fine. Despite this, however, Moon still can not get herself to trust Eclipsa and decides to leave with River, choosing not to oppose her rule out of respect for Star's decision to cede the throne to her.
While preparing to go to the beach with Marco and Tom, Star is called by Eclipsa, who reveals she got into a fight with Magic High Commission member Rhombulus, who created Globgor's crystal prison, to get him to undo the spell. Star attempts to get the two to peacefully reconcile, only for them to immediately start fighting again as soon as she turns her back on them. Eclipsa uses a spell that causes her and Rhombulus to switch bodies in order to undo Globgor's prison. However, Star convinces her to stop by pointing out that she will just prove herself the villain everyone claims her to be. Afterwards, Rhombulus angrily leaves, declaring he will never free Globgor, and Marco and Tom, seeing it is too late to go to the beach, make a kiddie pool cheer Star up.
Star and Marco journey to the Neverzone to rescue his friend Nachos from mysterious demons.
When a storm traps Star at Tom's family lake house, she turns it into a fun excursion.
Star and Marco turn into amateur sleuths to find who tried to turn Eclipsa to stone.
Moon and River try to adjust to life after giving up their crowns.
Star enlists Ponyhead to help make Eclipsa more popular.
Star tries her best to distract the Spider Bite family when Eclipsa is late for her first royal dinner.
Star, Marco and Janna want to take full advantage of Quest Buy's "Going Out of Business Sale".
Marco and Kelly risk life and limb to return a library book before it's overdue.
Star and Marco go on a perilous quest to break the curse of the Blood Moon.
Star tries to convince Buff Frog to move back to Mewni.
Glossaryck needs Meteora to help him with an errand.
Star and Marco have to make some decisions about the future.
Star and Marco have to rescue a kidnapped Eclipsa.
Tom learns how to have fun without Star.
Star and Eclipsa's spells come face to face, and they must team up to stop a lethal spell gone rogue.
Marco and Tom go on a dragon-cycling adventure.
Eclipsa has a date with Globgor.
Star plans a coronation for Eclipsa to become Queen.
Star attempts to figure out what to do with her life after she is not responsible for Mewni any longer.
Marco is determined to consume 50 tacos in order to win a special prize that is being offered at Britta's Tacos restaurant.
Star gets ready to actually have the day at the beach with Marco.
Marco misplaces both Mariposa and Meteora somewhere in Hekapoo's dimension.
Tom breaks up with Star but is not prepared for the consequences.
Star and Marco need Janna's help to return to Mewni.
Star, Marco, Janna and Tom lose their memories as they traverse amnesia-inducing waters to get back to Mewni.
Star arrives in Mewni as a soldier attacks Monster Castle.
Star, Ponyhead, Sea Horse, Kelly, Rich Pigeon, Jorby, Talon and Quirky Guy all arrive to bail out Eclipsa.
Moon arrives to save the day.
Moon and Mina agree to disagree.
Star searches for a way to defeat Mina and her Solarian Warriors.
Star attempts to solve all of her problems.