The Silence Before the Storm

After a month it was my birthday and also one of my other friends' birthdays. We decided to celebrate it together and take our friends out for a party. After some time it all started to die down and everything seemed to be fine. Then I got a call from a classmate who was not part of my group but we were still great friends. She told me that this professor came in between lectures and asked everyone in class where we were and no one said anything. Next day he punished every one of us, asked us to stand out of class and after class was over. He called myself and two of my friends to his office asking us where we all were. They all made excuses