Ho-sang's car is overturned on a journey with his wife, Min-jeong. She falls into a coma because of this accident and Ho-sang is distressed by her condition. One day, he finds a man's signature on his wife's book titled [Sundays in August] and gets jealous. He finds out that the man and his wife were planning to visit a mountain villa, and he decides to visit the villa by himself. Meanwhile Si-nae, Min-jeong's doctor, is interested in Ho-sang and the book [Sundays in August]. Si-nae calls So-kook in a secondhand bookstore to order the out of print [Sundays in August]. This book reminds So-kook of his dead friend.