Soul Eater Not! is a side-story to the main series, focusing on a freshman halberd named Harudori Tsugumi, who befriends two other meisters, Tatane Meme and Anya Hepburn. All three take part in the NOT (Normally Overcome Target) class at DWMA and learn to control their powers in order to overcome their difficulties to have a normal life, as opposed to the battle-oriented EAT (Especially Advanced Talent) class taken by Maka, Soul, and their companions.

At the Shinigami Weaponry Vocational School, humans known as Meisters study. Each Meister have their own partner, which is a weapon capable of taking on a human form. The story follows three of these Meisters and their Weapon.