When Lin Mo was eight years old, he met thirteen-year-old Jian Muning and thought this little brother was good-looking. In the misty and rainy water town of Jiangnan, because of the agreement made by the grandmothers when they were young, they will not meet again until their children and grandchildren are in the house. Two people who didn't know each other met. It was a childhood memory, but it was also the most unforgettable person.