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.

In the world of Remnant, humans and Faunus—human-animal hybrids—carry on their everyday lives despite the omnipresent threat of the monstrous Grimm. Dedicated Huntsmen and Huntresses battle Grimm with both customized weapons and their own "Semblances," unique abilities derived from the energy of one's soul. Some warriors also utilize a crystallized energy propellant, "Dust," to bestow their weapons with elemental properties. In this dangerous line of work, rigorous training is required to stay alive. To that end, each of Remnant's four Kingdoms have established schools to properly groom children holding aspirations of becoming licensed Huntsmen. At Beacon Academy in the Kingdom of Vale, a promising group of future Huntresses make their debut as Team RWBY. Ruby Rose, Weiss Schnee, Blake Belladonna, and Yang Xiao Long each come from different backgrounds and often butt heads as a result. However, when they cooperate, they are a formidable force who have even attracted the attention of Beacon's headmaster Professor Ozpin. Alongside fellow students such as those in Team JNPR, the young prodigy Ruby and her friends engage in adventures which pit them against an extremist Faunus group known as the White Fang. Every explosive encounter also brings them closer to the true villains orchestrating conflicts from the shadows.

The maid Lilith, hired to look after young Yuuri and his family's mansion, seems highly suspicious: she is too good to be true. Every dish she serves turns out to be delicious, the whole residence sparkles after she cleans it, and all the clothing has given off a pleasant scent since she started doing the laundry. Furthermore, her devilishly beautiful eyes only serve to heighten Yuuri's suspicions. Is Lilith perhaps a witch or a sorcerer? Yuuri cannot figure it out. But despite his misgivings, Yuuri has to live with Lilith as he tries to unravel the mystery behind her otherworldly charm.

Tooru Kirishima's notoriety is spread far and wide in the underworld. He is most commonly known as "The Demon of Sakuragi"—a man who is not afraid to resort to violence if deemed necessary. After almost jeopardizing a peace treaty, his boss tasks him with the most difficult job he has ever had: taking care of seven-year-old Yaeka Sakuragi—the boss' precious daughter—so that Tooru understands what it means to be responsible for another life. At first, the two do not seem to meet eye to eye, as Tooru has no clue on how to communicate with Yaeka, and the young girl is not used to expressing her emotions. However, as time goes on, they come to understand each other despite their differences. The fearsome right-hand man of a yakuza boss and the child he must protect are about to learn that family is not always bound by blood.