When Bae Suzy's autistic brother comes to her private school, she's determined not to let anyone know they're related. Even if that means losing contact to all her closest friends, including the charming football player Oh Sehun. But she just couldn't shake off the memoir of kissing Sehun last summer, and the desire to kiss him again. Can Suzy find the courage to tell Sehun how she really feels - and the truth about her family - before he slips away forever?