GREEN DAY《WAKE ME UP WHEN SEPTEMBER END》的MV讲的是什么内容啊？

wake me up when September end

　　Summer has come and passed
　　The innocent can never last
　　wake me up when september ends

　　like my fathers come to pass
　　seven years has gone so fast
　　wake me up when september ends

　　here comes the rain again
　　falling from the stars
　　drenched in my pain again
　　becoming who we are

　　as my memory rests
　　but never forgets what I lost
　　wake me up when september ends

　　summer has come and passed
　　the innocent can never last
　　wake me up when september ends

　　ring out the bells again
　　like we did when spring began
　　wake me up when september ends

　　here comes the rain again
　　falling from the stars
　　drenched in my pain again
　　becoming who we are

　　as my memory rests
　　but never forgets what I lost
　　wake me up when september ends

　　Summer has come and passed<