Eun-gyeol encounters Se-gyeong in her teens and learns a few things about her life that don't make sense in the future. Meanwhile, Yi-chan meets Chung-ah for the first time, but she doesn't say a word. Yi-chan tries to get away from Eun-gyeol, but Eun-gyeol follows him to the Snail Guesthouse and ends up becoming Yi-chan's math tutor.

恩杰以补习老师的身份入住李灿家的家庭宿舍，与曾祖母再遇，想起小时候短暂的回忆。另一边厢，恩杰意外地与世京见面，却不慎触怒她，令世京向恩杰和李灿发出警告…

恩傑以補習老師的身份入住李燦家的家庭宿舍，與曾祖母再遇，想起小時候短暫的回憶。另一邊廂，恩傑意外地與世京見面，卻不慎觸怒她，令世京向恩傑和李燦發出警告…

세경은 자신의 비밀스러운 가족사를 알고 있는 듯한 은결의 등장에 왈칵 불안해지고, 때마침 유학의 기회가 생기자 한국을 떠나기로 결심한다.

한편, 우연히 창고에 갇힌 청아를 발견한 이찬은 그녀가 학교에서 괴롭힘을 당하고 있다는 사실을 알게 되고, 필요할 때 도움을 청하라며 자신의 연락처를 주지만, 청아는 말할 수도 들을 수도 없다.

Eun-gyeol encontra Se-gyeong na adolescência e aprende algumas coisas sobre sua vida que não fazem sentido no futuro. Enquanto isso, Yi-chan conhece Chung-ah pela primeira vez, mas ela não diz uma palavra. Yi-chan tenta se afastar de Eun-gyeol, mas Eun-gyeol o segue até a Snail Guesthouse e acaba se tornando o tutor de matemática de Yi-chan.

อึนกยอลเจอเซกยองสมัยวัยรุ่นและได้รู้เรื่องบางอย่างเกี่ยวกับชีวิตของเธอที่ฟังดูไม่สมเหตุสมผลกับสิ่งที่เป็นในอนาคตเลย ในขณะเดียวกัน อีชานก็ได้พบกับชองอาเป็นครั้งแรก แต่เธอไม่พูดอะไรกับเขาเลยสักคำ อีชานพยายามจะหนีอึนกยอลให้พ้น แต่อึนกยอลตามเขาไปถึงหอพักหอยทากและกลายเป็นติวเตอร์สอนเลขให้อีชาน