Assassination Classroom

Chapter 1: Poison

They had all head back to the hotel with the medicine needed to cure their friends. When each of them had been given the medicine (except for Nagisa who hadn't been poisoned) they all fell asleep with their own exhaustion.  What they didn't know was that someone in the shadows was waiting for the right moment to strike at one of the students.  One in particular.

The next morning everyone had gotten up and headed to the lobby for breakfast. Korosensei noticed that a certain blue haired boy was missing.
" Karma-kun, have you seen Nagisa. " Korosensei asked
" He's not here? I swear I saw him walk to the washroom upstairs." Karma replied. Kayano overheard what they were talking about and said " He said he would be down in a minute when I called to him, but that was fifteen minutes ago."
Korosensei had a worried aura around him ( he has a smile plastered on his face). He looked around the students to see one more time if he was there, but the bluenette was nowhere around.

" Everyone please listen! If anyone has seen Nagisa please report to me!" Korosensei called out. The class went silent and whispers were heard through out the group of students. The silence was broken by the shattering of glass in the room next door. A loud clap was heard next and after that a thud. Karasuma, who was the closest to the door, looked at Korosensei. At Mach 20 Korosensei reached Karasuma with a gust of wind. The students surrounded the two teachers followed by Bitch-sensei.

When Karasuma opened the door, his eyes immediately widened. This was what he saw: a man who looked like he was in his thirties was lying on the floor. In his hand was a needle. Next to him was a young blue haired boy. He was breathing hard and passed out on the floor.

All the students looked at the scene and each of their eyes widened. Each one bigger then the other. Karasuma ran into the room and carefully put the young boy's head on his arm and checked his pulse. It was going unbelievably fast and he was breathing way harder then it was supposed to. All the students ran in and looked at the boy.
" What happened to Nagisa?"
" What the hell is going on?"
" Who is this guy?"
" Is Nagisa okay?"
The same questions were all over the students. It was broken when a dark aura came from a certain octopus at the back of the room. His face was pitch black. His veins popped out and his smile was slightly bent at the corners. 
" Karasuma, who is this man on the floor?" He said trying to keep his composure but everyone was as mad as he was.  Karasuma gently put Nagisa down and walked over to the man.  He checked his pulse and it was beating normally.  He then looked at the needle in his hand and took it out.  There was still a little bit of liquid in it but most of its contents were gone.  When Karasuma saw this he looked at Nagisa.  There was indeed a puncture wound on him.  It was on his arm.  Karasuma took his phone out of his pocket and dialled a number.