After getting caught up in an accident, Ryou Mihara is reincarnated in the world of Phi as a water magician. Waking up in a remote forest, he sets out to achieve his ideal slow life by living off monsters and refining his magic. Unbeknownst to Ryou, in his second life he has gained the hidden trait Eternal Youth. One day, Ryou stumbles across a shipwrecked adventurer named Abel. As Abel requests Ryou to accompany him to the town of Lune, they embark on a journey through mountains infested with monsters. Upon arriving at the town and registering as an adventurer, Ryou's powerful water magic and equipment are unlike anything anyone has ever seen before. Although his prowess piques the interest of many, Ryou is eager to begin his own adventure and hone his magic even further!

Prince Lloyd de Saloum—once a commoner who could never grasp magic—is now blessed with inexhaustible mana and has all the time in the world to master it, as he has no claim to the throne. After mastering demonic magic, he sets his sights on the Church to learn the secrets of divine magic that will bring him one step closer to completing his arsenal. However, due to his fondness for unholy magic, he draws the scrutiny of divine beings who see him as little more than a demonic spawn.

The Mikadono sisters—Miwa, Niko, and Kazuki—stand at the pinnacle of Saika Academy as its Three Royals, renowned respectively as prodigies in shogi, karate, and theater. Unfortunately, they have drifted apart from each other due to their overwhelming dedication to their fields, effectively turning them into strangers living under the same roof. Enter Yuu Ayase, the son of the late Subaru Ayase, a legendary actress who graduated from Saika. Unlike his mother, Yuu lacks any extraordinary talent whatsoever, much to the disappointment of those who knew her. Still, he transfers to her alma mater with one quiet promise in his heart: to fulfill her final wish that he build a true and happy family. It just so happens that the Mikadono patriarch is also Subaru's longtime friend and benefactor, and he offers Yuu both a place to stay and a fresh start. Thrust into the lives of three estranged sisters who act cold toward him, Yuu may not be a genius himself, but the clumsy sincerity he brings might be what they all need to start anew.

After the success of his crowdfunded movie featuring the woman of his dreams, Chizuru Ichinose, university student Kazuya Kinoshita resumes his life of lies and deception. Although he pretends that he has been in an ideal relationship with Chizuru for more than a year, Kazuya still mostly sees her through a rental girlfriend company's services. However, after Kazuya attends a private party with Chizuru, he reaches the decision to finally confess his feelings to her. Unfortunately for him, his trial girlfriend Ruka Sarashina and his ex-girlfriend Mami Nanami continue to complicate his already messy attempts at romance. While he is forced to keep up his facade, Kazuya is under pressure to find a solution to his ever chaotic love life.