Star and Marco are having Captain Blanche's Sugar Seeds at midnight so that they can gorge. Star finishes off her bowl, but when she notices that she has one marshmallow left, she takes one out of her mouth and leaves it as a cute gesture. She heads off to bed, but Marco lingers on the bowl for a while in an enamored sense. He goes to see Eclipsa, who is cleaning Globgor's crystal, and tells her about his feelings for Star which are still prominent. She sympathizes, but tells him that it is not something he should be ashamed of. Janna approaches Marco and offers to help him, despite his bad experiences with her, and she knocks him out. 14 hours later, Marco wakes up in the bathroom and still has lingering feelings for Star, much to Janna's disappointment. Marco decides to confront Star.
Star is in her room with Tom playing with the laser puppies when Marco nervously walks in along with an intrigued Janna. He comes out to her about the cereal and his linked feelings for her, which she also realizes that she still has. Tom, who is not upset, reveals that this is the result of the Blood Moon Ball they went to a year ago and reveals that it is actually a curse. He offers to remove it for them and they both happily agree. The group head to Grandpa Relicor's study to look up the information on the Blood Moon and learn that in order to break the curse they would have to wait an additional 665 years until it comes back to remove it, much to Star and Marco's horror. Relicor reveals himself and presents a book that offers another way of removing the curse: the Severing Stone. The group take a demon elevator to the Underworld.
The group is forced to sever the rope to reach the bottom floor of the Underworld as the demon carrying them refuses to press on. Upon reaching the bottom, they find a rickety bridge with the severing stone across on the other side. A tower rises, revealing a demon named Abraxacan and Marco, in a frustration induced state, deduces that he wants him and Star to carry a couch up the tower's steps as a way of proving themselves. Before they can however, another demon named Vexicor arrives and angrily tells them to go ahead as he was going to hire movers to do it. The group make it across and find the stone which speaks to them in noises. Relicor proceeds to screech something to it that causes him to cry. Tom reveals that the stone will sever the curse from them, but they have to give up the memory of the moment permanently.
Star and Marco step up on the pedestal and suddenly find themselves back during the events of "Blood Moon Ball" and recreate the dance, though it seems to go on longer. They begin to appreciate the moment when they find themselves back in the real world. Marco no longer finds the leftover cereal cute and he only sees Star as his best friend, relieving them. Tom apologizes for keeping the information of the curse to himself and Star forgives him. Janna proceeds to use the stone on herself and severs her own soul in two, claiming to be a demon now, though Tom, annoyed, tells her that is not how it works.
- Eden Sher as Star Butterfly
- Adam McArthur as Marco Diaz
- Rider Strong as Tom Lucitor
- Abby Elliott as Janna Ordonia
- Esmé Bianco as Eclipsa Butterfly
- This is the eleventh half hour-long episode in the series, following "St. Olga's Reform School for Wayward Princesses", "Storm the Castle", "Bon Bon the Birthday Clown", "Face the Music", "Starcrushed", "Monster Bash", "Divide", "Conquer", "Butterfly Follies", and "Escape from the Pie Folk".
- Tom calling Relicor his "grandpa-pa-pa-pa-pa-pa-pa-pa-paaaaaa" may be a reference to the series' theme song.
- Eclipsa is shown to have known about Marco's feelings for Star prior to this episode.
- Janna is stated to have hypnotized Marco to hate nachos.
- Additionally, Janna's "chickenbutt" hypnotism from "Deep Dive" is brought up again.
- The events from "Blood Moon Ball" are directly referenced.
- Tom states that the next Blood Moon is 665 years. Since the Blood Moon occurs every 667 years, it has been two years since the events of "Blood Moon Ball".
- May 31, 2019 (Southeast Asia)