Yu-No Episode 4

Takuya's world was turned upside down when his father died in a tragic research accident. Concerned for his young stepmother, Ayumi, he decided to follow her to Ken Point. There, he spied on her and her best friend Mitsuki from behind a rock. Suddenly, a blinding flash of light materialized into a stunning, otherworldly woman. Before he knew it, she slipped a mysterious ring onto his finger, and just like that, Takuya's journey into a parallel universe began. This ring, it turns out, is the magical link that connects Takuya to his alternate realities.