What's the story in the MV of the longest song movie?

The general plot is: boys and girls are classmates, have a good relationship and often play together: skating together, boys punch in front of girls. One day someone bullied the girl, and the boy got into a fight with those people. The boy was very weak and was beaten black and blue. The next day, the girl was leaving (probably an immigrant) and gave the boy a hair band before leaving. . . . . .

After many people watched it, the boy grew up (played by Jay Chou) and drove for others. The hair band that the girl gave him hangs in front of the driver's seat of the car. Once, a boy drove past a place and saw many gangsters around a girl. The boy walked over and took care of those people with three strokes. At this time, the boy found that the girl was the one he had been waiting for. When the boy drove the girl home, the girl asked the boy, "Why are you so powerful?" The boy said, "Because I have someone in my heart to protect." The girl found the headband in the driver's seat and asked the boy if he could show it to him. The boy took off his headband and gave it to the girl. The girl looked at the headband and remembered everything. . . . .

At this time, the gangster came with the guy to avenge the front. A blunt object fell and smashed the window. . . . . .

The last shot left a suspense for the audience. )