So the story truly begins when Harry and Hermione meet a werewolf, whom they really don't know. They went to Romania for a Potions assignment. As they were walking through the woods, they met him. They were walking collecting samples for the Potions project, when suddenly a bad tempered werewolf jumps out and lunges at them. They immediately noticed that if they didn't find a way to calm down his temper that they would have to fight. So they went and collected potion ingredients for a Wolfsbane Potion to soothe the werewolf. After they convinced him to drink it, they were able to talk with him.
Once they were done talking, the werewolf realized they meant him no harm and swore not to attack. After that, there was an unspoken agreement to become friends.They knew the werewolf would be able to control himsself except for during the full moon and readily agreed to take him to Hogwarts to meet Remus Lupin, their werewolf friend. It was easy enough to lead him to the others. Convincing Snape was a different matter. Hermione had to use all her charm as well as promise to collect extra potion ingredients. Finally, Snape allowed them to bring him back, making sure they knew that if the werewolf harmed anyone, they would all pay dearly.
So they went back to Hogwarts. The castle made the werewolf uneasy, since as a wild animal, (at the moment, anyway) he hated being caged in. After a lot of reassuring, they were able to lead the werewolf to the Defense classroom. As Lupin came to greet them, he reeled back in shock as he noticed the werewolf. Hermione and Harry both had to talk fast so as to not get into trouble. Soon Lupin and the werewolf were talking to each other, Lupin coaxing him to drink more Wolfsbane. Hermione and Harry smiled. They knew that if anyone, Lupin, and Lupin alone, could help teach the werewolf to control the animal inside.