Nao is a replica created to be Sunao Aikawa's perfect double, stepping in whenever Sunao skips school. She studies, plays sports, and lives each day for the original-until one day, Nao falls in love. Suddenly, her quiet, borrowed life blooms with secret dates and shy promises. But the more she cherishes them, the more she must hide from Sunao, who's starting to notice the changes in her replica.