Set in the fictional Death City, "Soul Eater" revolves around students of the Death Weapon Meister Academy (DWMA), an institution founded by Shinigami, the Grim Reaper himself. The academy trains individuals known as Meisters and their weapon partners, who can transform into humanoid weapons. The primary goal of the students is to collect the souls of 99 evil humans and one witch to transform their weapon partners into "Death Scythes," powerful tools used by Shinigami to maintain balance in the world.

The story primarily follows three Meister-Weapon pairs: Maka Albarn and her scythe partner Soul Eater, Black☆Star and his weapon Tsubaki Nakatsukasa, and Death the Kid with his twin pistols, Liz and Patty Thompson. Maka and Soul aim to collect souls to perfect their partnership, but their journey is complicated by Soul's occasional struggles with his inner demon, the Black Blood. Black☆Star, a brash and overconfident ninja, seeks to surpass his clan's legacy, while Tsubaki provides a calm and supportive counterbalance. Death the Kid, Shinigami's son, battles his obsessive-compulsive tendencies and strives to prove himself despite his perfectionism.

The narrative escalates when the DWMA faces threats from the Kishin, malevolent beings born from madness. The primary antagonist, Asura, is a Kishin who seeks to spread chaos and fear. Asura's resurrection triggers a series of events that force the students to confront their fears, insecurities, and the darker aspects of their powers. The series explores themes of courage, partnership, and the struggle between order and chaos, as the characters grow stronger and face increasingly dangerous foes.

The world of "Soul Eater" is rich with supernatural elements, including witches, demons, and magical abilities, all tied to the central concept of souls and their resonance. The characters' development is closely tied to their relationships with their partners, emphasizing trust and synchronization. The story balances action, humor, and darker tones, creating a dynamic narrative that keeps the stakes high while allowing for moments of levity and camaraderie among the cast.