After several years apart, she still remembered his voice and appearance. He had really changed too much. He was no longer the young boy she knew. But she still couldn't forget him or the three years in high school. Now she is 29 years old. She has met a lot of people, seen a lot of scenery, and had many kisses, but there is still no one who makes her heart beat. Now that I saw him, I felt a little sour. Suddenly one day, I woke up and found myself in a high school classroom. What was going on?