World-class medical researcher Kanji Yakutani lost his little sister to a tumor years ago due to ineffective treatment. To honor her legacy, he has dedicated his research to developing new medications for such conditions. But as fate would have it, he overworks himself and passes away at the age of 31, only to be given a second chance at life in another world. When he wakes up, Kanji finds himself in the body of a 10-year-old boy named Falma de Médicis, the son of an esteemed family of medical practitioners in the Sain Fleuve Empire. Bearing the mark of a deity's divine blessing, Falma is capable of performing a unique divine art, allowing him to create and reduce any substance with the knowledge of its chemical properties. After reading through some pharmacology books, Falma realizes that this world is operating on similar medical practices as in ancient times. He also learns that medicine is an exclusive privilege to the nobility, depriving commoners of proper medical care. Using the knowledge from his past life and the divine abilities granted to him, Falma resolves to make medicine available to those who need it—irrespective of class.

After Musashi rescues Michiru Saruwatari from a demon, his friend Kojirou Kanemaki discovers that his father was a member of the Uesugi clan. Determined to learn more about his own past, Kojirou—alongside his Kanemaki clansmen—decides to participate in Uesugi's punitive expedition against the demon lord of Awajima Island: Yamata no Orochi, an eight-headed dragon that threatens to engulf the entire region. However, upon joining Uesugi's military alliance, Musashi faces the harsh reality of fighting against powerful demons. Humiliated by his lack of power and inability to work in groups, he has to learn how to cooperate with his newfound allies. Meanwhile, the Obsidian Eight—a group pursuing the Obsidian Goddess that dwells within Musashi's body—resumes its hunt for Musashi, and plans to thwart the ongoing island operation. As the situation grows chaotic, Musashi and his friends must foil the machinations of the various factions conspiring to seize the Obsidian Goddess.

Ichigo Momomiya is excited to start high school and fall in love. She is in luck when she meets the popular and good-looking Masaya Aoyama, and she immediately develops a crush on him. When Ichigo learns that Aoyama is passionate about the environment, she seizes the chance to ask him out thanks to some tickets to an exhibition about endangered animals. During their date, Ichigo is struck by a mysterious light and faints. Waking up to the sight of Aoyama, she remains unharmed—but they both must escape from a giant rat-like creature after it injures Aoyama. To save her crush, Ichigo awakens her powers and transforms into a heroine with the skills of a cat. After she defeats the monster, researchers Ryou Shirogane and Keiichiro Akasaka explain that Ichigo was chosen to become a part of the Mew Project: a group of five magical girls whose DNA has been infused with those of certain endangered species. Now, Ichigo must find the rest of her teammates to defeat the Chimera Anima—beings infected by aliens who want to take over the world—before it is too late.

The original episode will serve as a bridge between the second and third season.