Kaori and Haruka, mother and daughter, have loved Kokoro like family since she was little. Now that Kokoro has grown up a little and is wearing a uniform, Kaori and Haruka begin to love Kokoro as a woman. What will be the outcome of love that Kokoro will reach as she begins to climb the stairs to adulthood? A deep and sweet love story spun from a forbidden love triangle between best friends, a best friend's mother and her daughter's best friend.