Star's best friend from her home dimension pays a visit and feels threatened by Star's new friendship with Marco.
Star is ready to try "Marco's Super Awesome Nachos" when they get an unexpected visit from her bestie from another dimension Princess Pony Head. Pony Head claims that she came by because she just wanted to visit and heard that Star was staying on Earth. Marco immediately becomes uncomfortable with her because of her somewhat rude and obnoxious behavior, but Star convinces him that they should hang out so that "[her] besties can become besties". Pony Head reveals that she possesses dimensional scissors which allows anyone to travel to any dimension in thin air. After they leave however, a group of masked men arrive apparently looking for Pony Head.
The trio end up in the Bounce Lounge, a techno club on clouds suspended over a spiky gorge, which Star cautions Marco about. She drags the three into a photo booth, but when Star leaves Marco and Pony Head together, the latter begins threatening the former over interfering with their friendship, leaving Marco worried. Marco attempts to warn Star about Pony Head which results in her trying to knock Marco into the gorge. When Star rescues him, she admits that Pony Head can be possessive and she tries to talk to her about trying something Marco likes. While Pony Head tries to be dismissive, she changes her tune about seeing the masked men from earlier and drags the two to the Amethyst Arcade, an interdimensional arcade populated with nerdy square people. Marco and Pony Head challenge each other to Lance Lance Revolution while Star goes to get icicles. When Pony Head sees the masked men, she abandons Marco and drags Star to the next dimension while the masked man capture Marco.
At a concert, Star realizes that Marco is not there and Pony Head bluntly admits that she left him. Upset that Pony Head would do that, she tells her that she can have two besties and that she cares about them equally. Pony Head and Star head back to rescue Marco and after a chase are confronted by King Pony Head who reveals that the men are guards from St. Olga's Reform School for Wayward Princesses. Pony Head apologizes for her behavior as she just wanted one more night with Star before leaving. She leaves the dimensional scissors with Star and she and Marco head home to have nachos.
- Eden Sher as Star Butterfly
- Adam McArthur as Marco Diaz
- Jenny Slate as Pony Head
- Maurice LaMarche as St. Olga's Guard, King Pony Head, Squares
- Eddie Deezen as Squares
- Corey Burton as Lance Lance Revolution Announcer
- This is the first instance of Marco being called an Earth Turd.
- Lance Lance Revolution is, of course, a nod to Dance Dance Revolution.
- The Squares at one point fall into place similar to the game Tetris.
- April 6, 2015 (Canada)
- April 16, 2015 (United Kingdom and Ireland)
- June 3, 2015 (France)
- June 12, 2015 (South Korea)
- July 18, 2015 (Romania, Bulgaria)
- July 20, 2015 (Germany)
- August 15, 2015 (Czech Republic, Hungary)
- August 3, 2015 (Australia)
- August 22, 2015 (Latin America)
- September 1, 2015 (Israel)
- October 5, 2015 (Turkey)
- October 19, 2015 (Poland)
- October 24, 2015 (Spain)
- Fall 2015 (Russia)
- November 2, 2015 (Italy)
- November 8, 2015 (Southeast Asia)
- December 18, 2015 (Japan)
- December 19, 2015 (Portugal)