For 500 years, the Taboo Emperor, Arthur Gaz, ruled the Gaz Empire with an iron fist and conducted inhumane experiments on his own people. But his reign came to an end five years ago, when mighty warriors—later known as the Eight Heroes—defeated him in a battle for the capital. His death ended the 300-yearlong war between the Gaz Empire and the alliance of six nations. In the present day, Tooru Acura is a former saboteur from the war who has difficulty settling into the peaceful world, as he cannot find a job where he can put his fighting skills to use. An opportunity appears before him, however, when he meets a white-haired Wizard named Chaika Trabant. With a coffin on her back, she is searching for the scattered remains of her father in order to give him a proper burial, and she hires Tooru and his adoptive sister Akari to help her. However, the six nations alliance, which have now formed the Council of Six Nations, dispatches Albéric Gillette and his men from the Kleeman Agency to pursue and apprehend the late Emperor Gaz's daughter—Chaika. With the shocking revelation of Chaika's identity, the Acura siblings must choose between helping her gather the remains of the tyrannical emperor and upholding the peace the continent strives to maintain.

Soul Eater NOT! is a spin-off and side story that takes place one year prior to the events of the original Soul Eater. At the Death Weapon Meister Academy, humans born with the power to transform into weapons and those with the power to wield these weapons (Meisters) train to hone their natural talent. The characters of the main series are enrolled in the Especially Advantaged Talent class, where they train to become warriors of justice capable of defeating what threats prey on innocent lives—or even the entire world. Other students at the DWMA are less talented. Members of the Normally Overcome Target class focus less on being warriors of justice and more on controlling their powers so they don't hurt themselves or anyone around them. Tsugumi Harudori, a new halberd-transforming student, meets Meisters Meme Tatane and Anya Hepburn and quickly grows indecisive about which of the two new friends should be her partner. As they learn to use these powers and settle in, their lives as everyday students will be far from normal.

One night, right before summer vacation, Manatsu Daichi, a second-year in high school, sees a weird round rainbow floating in the sky above Tanegashima and ventures there alone. He has seen this rainbow before. With the memories of his father's mysterious death and an encounter of a strange boy and girl, Daiji arrives on the island while the alarm of a building labeled Earth Engine is going off. Someone asks him if he is a captain, just as robotic intruders from Uranus called Kill-T-Gang arrive. The battle around the shining stars is about to begin. (Source: ANN)

The search for the remains of Emperor Gaz continues. Chaika still in search of knowing who she really is and what her purpose is. Similarly, the Red Chaika continues the search for the rest of Emperor Gaz's remains. The Gillette corporation continues the mission to catch every last Chaika. In their adventure they give a revealing account kept secret by the Emperor, which Chaika, Fredrica, Toru, and Akari decide to uncover. (Source: ANN, edited)