Spring has finally arrived in Moomin Valley, giving way to another great adventure for Moomintroll and the rest of its inhabitants. With Snufkin coming home from his winter migration, the locals of the valley finally begin to rise from their hibernation. Finding a mysterious hat, the Moomins cannot bring themselves to throw it away due to its fine quality, instead hoping to eventually find its owner. While playing games with his friends, Moomin tries to hide in the silk hat. When his friends come looking for him, they are shocked to discover that Moomin has transformed into a hideous creature. Examining himself in the mirror, he is disgusted to find himself completely unrecognizable. Transforming back to normal after scaring his friends and family, Moomin and Snufkin decide to toss the hat in the river. As it drifts away, they begin to wonder who the hat belonged to and whether its owner will return for their lost possession.

Chise Hatori, a 15-year-old Japanese girl, was sold for five million pounds at an auction to a tall masked gentleman. Abandoned at a young age and ridiculed by her peers for her unconventional behavior, she was ready to give herself to any buyer if it meant having a place to go home to. In chains and on her way to an unknown fate, she hears whispers from robed men along her path, gossiping and complaining that such a buyer got his hands on a rare "Sleigh Beggy."

Ignoring the murmurs, the mysterious man leads the girl to a study, where he reveals himself to be Elias Ainsworth—a magus. After a brief confrontation and a bit of teleportation magic, the two open their eyes to Elias' picturesque cottage in rural England. Greeted by fairies and surrounded by weird and wonderful beings upon her arrival, these events mark the beginning of Chise's story as the apprentice and supposed bride of the ancient magus.

[Written by MAL Rewrite]

Having freed a myriad of women from the runaway spirits possessing their hearts, the "God of Conquest" Keima Katsuragi is confronted with a new task: find the Jupiter Sisters, the goddesses that sealed Old Hell in the past. Diana, the goddess that resides inside his childhood friend Tenri Ayukawa, explains that they have taken shelter in the hearts of the girls he had assisted previously. Moreover, once Diana and her sisters are reunited, their power can seal the runaway spirits away for good and relieve Keima of his exorcising duties. Though he is initially reluctant to get involved in yet another chore, everything changes when tragedy befalls one of the hosts. Discovering that the goddesses are being targeted by a mysterious organization known as Vintage, Keima is caught in a race against time to reunite the sisters and rescue the girl who has already fallen prey. With deeper resolve than ever before, Keima works together with demons Elsie and Haqua to recapture the hearts of the girls he had charmed in the past. However, the road ahead is a difficult one, as he is soon met with the consequences of his previous conquests. [Written by MAL Rewrite]

Kazuya Kujou is a foreign student at Saint Marguerite Academy, a luxurious boarding school in the Southern European country of Sauville. Originally from Japan, his jet-black hair and dark brown eyes cause his peers to shun him and give him the nickname "Black Reaper," based on a popular urban legend about the traveler who brings death in the spring. On a day like any other, Kujou visits the school's extravagant library in search of ghost stories. However, his focus soon changes as he becomes curious about a golden strand of hair on the stairs. The steps lead him to a large garden and a beautiful doll-like girl known as Victorique de Blois, whose complex and imaginative foresight allows her to predict their futures, now intertwined. With more mysteries quickly developing—including the appearance of a ghost ship and an alchemist with the power of transmutation—Victorique and Kujou, bound by fate and their unique skills, have no choice but to rely on each other. [Written by MAL Rewrite]