[Rebecca Shoichet] Sunset Shimmer and [Andrea Libman] Pinkie Pie head to the Starswirled Music Festival, a two-day live event, eager for a reunion by PostCrush, the group’s favorite pop duo, comprising vocalist/guitarist [Lili Beaudoin] Kiwi Lollipop (K-Lo) and drummer [Mariee Devereux] Supernova Zap (Su-Z).
On the first day, Sunset Shimmer copes with a string of small annoyances, many of them caused by an easily distracted Pinkie Pie. When Pinkie destroys a churro cart, the two are kicked out, and Sunset angrily rejects Pinkie’s attempted apology. As Sunset sits on a hilltop overlooking the festival site, a surge of magical energy washes over her, signaling that something extraordinary is beginning.
When Sunset wakes up the next morning, she discovers she is reliving the first day of the festival. She tries to keep Pinkie from getting sidetracked, but Pinkie again breaks the churro cart, and both of them end up expelled from the grounds once more. On the next repetition, Sunset decides to cut Pinkie out of the plan, snagging a front-row spot to see PostCrush, unaware that Pinkie’s heartbreak and the others’ disapproval are still brewing behind her choice.
Sunset is stunned to find that she remains stuck in the same day, looping time after time even after she seemingly achieves her goal, and she begins to blame Pinkie for the situation. After a couple of weeks in the loop, she attempts a drastic move by driving Rarity’s RV away in the middle of the night to break free, but the plan fails when the vehicle breaks down and traps her in the loop once more. The next day, she reaches out to Princess Twilight Sparkle in Equestria, and [Tara Strong] Twilight Sparkle replies that the loop is caused by a magical artifact known as the Time Twirler. Sunset resolves to locate the user of the artifact and put an end to the loop.
The group initially suspects that the Time Twirler is connected to a performance by the Sirens/Dazzlings, whose song seems to guide Sunset toward the artifact. However, [Kazumi Evans] Adagio Dazzle explains that they never regained their magic after losing it, and they have nothing to do with the time loop. With a renewed sense of purpose, Sunset chooses to treat Pinkie better and indulges her in a variety of activities during another cycle. The friends manage to sneak backstage to meet PostCrush and learn that the duo found the Time Twirler on the night before the festival, using its spell to reset the day whenever a mishap threatened their flawless set.
A security guard initially ejects them, but he later readsmit them, and just as PostCrush’s show begins, Pinkie knocks the Time Twirler off K-Lo’s hair bow while Sunset smashes it to the ground, breaking the spell for good. Kiwi Lollipop and Supernova Zap are left desperate at first, but Sunset reassures them that their fans want to see them perform and have fun, not chase perfection. The duo apologizes and reconciles, delivering a lively performance alongside Sunset and Pinkie.
The next morning, Sunset is delighted to learn that a new day has begun—the second day of the festival. She notes that she has been in the loop for three weeks and decides to spend the day with Pinkie, embracing the chance to enjoy the moment without repeating it again.
