Volume 1

Ansatsu no jikan (暗殺の時間) is the first volume of the Assassination Classroom manga.

Preface
''Ever caught yourself screaming, "I could just kill that teacher"? What would it take to justify such antisocial behavior and weeks of detention? Especially if he's the best teacher you've ever had? Giving you an "F" on a quiz? Mispronouncing your name during roll call...again? How about blowing up the moon and threatening to do the same to Mother Earth—unless you take him out first?! Plus a reward of a cool 100 million from the Ministry of Defense! Okay, now that you're committed... How are you going to pull this off? What does your pathetic class of misfits have at their disposal to combat Teach's alien technology, bizarre powers and...tentacles?!''

Publisher's Summary
Meet the would-be assassins of Class 3-E: Nagisa, who quietly analyzes his classmates and targets. Sugino, who let his grades slip and got kicked out of the starting lineup of the baseball team. Karma, who's doing well in his classes but keeps getting suspended for fighting. And Okuda, who lacks both academic and social skills, yet excels at one subject: chemistry. Who has the best chance of winning that reward? Will the deed be accomplished through pity, brute force or poison...? And what chance does their teacher have of repairing his students' tattered self-esteem?

Chapter 1: Assassination Time
The day starts with Class 3-E waiting for their octopus teacher, who then walks into the classroom. He sets the roll book on his desk and starts homeroom. He tells the student who's on command duty to issue it. Nagisa Shiota, the student on duty, calls the command and all of the students stand ready with their firearms, ready to shoot. On "Bow" they begin mass firing and the teacher takes roll call while dodging the bullets. After he finishes, he commends the class for no absences and the students are upset that they didn't land a single blow. The teacher tells them that tactics that rely merely on numbers lack individual thought and that they should devise a more creative plan or else they won't be able to kill him with his maximum speed of Mach 20. The students begin to complain that there was no way he could have dodged all the BB Pellets and that they wouldn't have had an effect on him. The teacher then shows them that those weapons do in fact work against him by blowing off his arm and tells him that the weapons are only effective against him and are harmless to humans, but it'll still be dangerous if they were to shoot their eyes out and that they should not fire indoors unless they are trying to kill him. After that he tells the class that he hopes they can kill before graduation while having his mocking face on and the class starts to clean up the bullets.

While class takes place, Nagisa thinks back to how this all started and how they ended up with this octopus-looking teacher. It stared with the moon being blown up into a permanent crescent a few weeks prior and shortly after, the one who claims to be responsible shows up in Class E and states that he'll be their new homeroom teacher. This causes the class to enter a state of disbelief and Tadaomi Karasuma to explain the situation.

Chapter 7: Toxin Time
The class had just finished a food coloring experiment when Manami Okuda approaches Korosensei at his desk and asks him to drink her poisons. While the class silently laments her straightforwardness, Korosensei proceeds and poison only go as far as affecting his appearance. After gently reprimanding her for making dangerous poisons such as thallium acetate and sodium hydroxide, he offers to help her create a poison that will work on him.

Extra: Korosensei's Drawing Song
A short, two page extra about Korosensei singing of drawing his own face on the eastern side of the globe. It starts with placing a bean in Tokyo then placing one in China's Sichuan province. Then you fly from Dubai to Hawaii, leaving a vapor trail then returning to Dubai from Hawaii while passing over the Philippines. Between Hawaii and Dubai you then fly vertically at intervals of 20° longitude (all before the vapor trail disappears) and at last you have Korosensei. The extra ends with Korosensei telling the students of Class E to go and try drawing it for real and them replying that they can't.

Author's Comment
''"Kill" is a fascinating word. It's often used but rarely put into action. Often, when people say they will kill another, they don't. It's what I wanted to prove, so I decided to create a story centered around this unique word. If you enjoy it, you can kill me now and I'll die happy.''