Kato Hina originally learned braille for her father, who had lost his sight. Chased by debt collectors because of the money her twin sister Yuna borrowed, Hina ends up working in place of Yuna as a live‑in helper for Kuramae Ritsu, a visually impaired company president. Thanks to Hina’s patient and devoted care, the once‑lonely Ritsu gradually opens his heart, and the two begin to fall for each other. However, after Ritsu regains his sight through surgery, Yuna approaches him while pretending to be Hina, frames Hina, and even becomes engaged to him. A year later, a wounded Hina appears before Ritsu again—this time as the adopted daughter of his father, effectively becoming Ritsu’s “stepsister.” Ritsu finds himself once more drawn to Hina, but Yuna lies that she is pregnant, and Ritsu’s younger brother proposes to Hina to shake Ritsu’s resolve. In the midst of this turmoil, Hina realizes there is a mastermind pulling the strings behind everything…