Their homeroom teacher is an octopus-shaped creature with the power to destroy the planet, and he has given Class 3-E one school year to assassinate him before he does it. He also marks their homework, and he wants it on time.

Yusei Matsui wrote and drew Assassination Classroom for Shueisha's Weekly Shonen Jump between July 2012 and March 2016, collected in twenty-one volumes. The cast is the bottom class of a junior high, the misfits parked in a separate building away from the main campus, handed weapons and a target instead of the usual remedial lecture.

Matsui runs two registers at once and keeps both honest. Half the series is gag comedy built around a creature whose shape can carry any punchline, and around thirteen-year-olds treating assassination as a group project with a deadline. The other half is tactical action: planning, formations, feints, and the standing problem of landing a hit on something that outclasses you on every measurable axis. Science fiction supplies the premise, then gets out of the way.

It suits readers who want shonen with a fixed finish line and a clean structure, and it rewards anyone who likes school stories where the teaching is real. Start at volume one. The setup lands inside a dozen pages, and it holds for all twenty-one.