片翼のラビリンス

Oguri Miyako, an ordinary high school girl with a crush on her classmate Hiroto, is heartbroken to see him kiss her older sister Hotaru. When a mysterious key falls into her hands, Miyako gains the power to time leap, sending her two years into the past to rewrite her fate. Alongside the enigmatic Tsukasa, who seems to know more than he lets on, she navigates love, regret, and the consequences of changing time in this emotional tale of romance and destiny. (Unreviewed summary by Grok 2)