Narikawari Reijou no Loop Line Kurikaesu Sekai ni Shiawase na Ketsumatsu wo

"Since you've come this far, I'll make you glad you chose me."

Sakura is entrusted with a "mission" by a friend. That mission: to become Rosie, the protagonist of her beloved book, "The Fairy Princess Tale," and avert the tragedy that unfolds in this world and stop the repeating loop. But she fails the first time—she dies and returns to her hometown two years ago, and seeks help from her favorite character, her childhood friend and prince of a neighboring country, Yule. If possible, she wants to save him as well, as he is destined to die.

To save her loved one, the substitute young lady defies fate with all her might.

(Source: Kadokawa, translated)