After the war was over, and everyone was starting to get their lives back together, many of the younger survivors came to a startling realization that life goes on. Your academic marks at school will start to matter, and even though you have fought in a war to ensure the safety of your fellow wizards and witches, your resume still has to be top notch.
While many graduated from Hogwarts, those heavily involved in the war had actually gone back to school and finish up their seventh year. Headmaster McGonagall extended an invitation for those few students who didn't have to opportunity to finish up school but may still have been interested in it. Ron was drafted by the Chudley Cannons and therefore had no real desire to go back to Hogwarts. Harry was, well, he was Harry Potter, so when he was asked to take a high position in the Department of Magical Law Enforcement, he graciously took the job and also decided not to further his education.
Hermione however, the knowledge seeking bookworm she was, decided that returning to Hogwarts for her final year would be what would work best for her. She also saw it as a return to normalcy, and the opportunity to attend classes and learn without worrying about being murdered in your seat b a Death Eater at any moment. Also wanting some semblance of stability, Ron and she both decided that having a long distance relationship would put a rather large strain on their friendship, something neither was willing to risk. After their amicable break up, it was clear to Hermione that she needed to dive into some books and move on with her life.
Unfortunately for her, the only other student in her class that was heavily involved with the war was one Draco Malfoy, and he was also offered the same invitation. At first, the likelihood of attending the last year seemed bleak, with the constant tabloids being written about the Malfoy family, both Lucius and Narcissa decided that it would be best for their only child to be somewhat hidden from the public eye for the time being.
This leads into how these two found each other sitting in front of Headmaster McGonagall's office a week before the start of a new session.
"I brought you both here to let you know that you have both been chosen to be Head Boy and Head Girl this year."
Hermione gaped, with her mouth wide open in shock as Draco, who had been playing with the ends of his cloak, stopped only to stare at the new Headmaster as though she had gone mad.
"I took this into deep consideration over the summer, and after thinking about what Dumbledore might have wanted, I think the both of you bring in two very different types of experiences and personalities that will be very beneficial to your other classmates. This year especially, unity is important, and it is important to show that even with all your differences, you two can put it aside for the better of the school, and for the better of the wizarding community."
Hermione tried to come up with some sort of rebuttal, but failed. She looked to Draco for some sort of resistance, but he still seemed to be taking in all that had been said.
"I understand if either of you are unwilling to take on this responsibility, and I do have a couple of students in mind in case you two reject my offer, but please take it into consideration."
"I'll do it."
Hermione looked over at Draco who had been stone quiet up until that point. It might have been the first time she had heard him speak since the last time they had seen each other in the battlefield. Never to be outdone; "So will I."