With the tumultuous cultural festival behind him, Masamune Makabe continues his efforts to carry out his revenge: to make the Cruel Princess Aki Adagaki deeply fall for him and then immediately dump her. As his class is going on a trip to Paris, widely known as the City of Love, Masamune has the perfect opportunity to get even for his childhood heartbreak. Before Masamune can impress Aki, the two meet Muriel Besson, a French high school otaku who aspires to create a romantic comedy manga series. Muriel believes Masamune is the ideal model for the protagonist and asks for his help. The boy reluctantly agrees, dragging Aki along to provide inspiration for the love interest's character. But to do so, the two must show Muriel what Japanese love is like. To make matters more complicated, Kanetsugu Gasou is masquerading as Aki's childhood friend, Masamune, to trick and use her. With mix-ups and love rivals galore, Masamune's revenge is proving to be quite the difficult task.

A decade ago, 450-year-old vampire Ranmaru Mori was saved from the brink of death by Rihito Tatsuno, a young and innocent boy. Ever since then, Ranmaru has been working at the Tatsuno family's bathhouse with a secret: he wants a taste of Rihito's virgin blood as soon as he turns 18. However, his plan is threatened when Rihito falls in love with a girl on his first day of high school. Jealous and scared that Rihito's pureness will be ruined, Ranmaru begins to lurk in the shadows to protect him from any harm. During his operation, the vampire must keep his real identity hidden and make sure his target's virginity remains unsullied.

Shin Hazama has shut his heart ever since the mysterious and sudden death of his mother during his childhood. With his scientist father occupied with research, he can only rely on his childhood friend, Kotori Izumi, the popular and good-natured daughter of his father's employer. At the end of their third year of high school with graduation right around the corner, Shin and Kotori finally begin to move forward together, both in life and in love. Everything falls apart again when Shin's father also suddenly dies. But before things can settle down, he and Kotori learn the secret behind his parents' sudden deaths when they encounter agents from a high-tech dystopian Japan existing in a parallel universe. Among them is Jin, Shin's relative self, who is working against the humanoid weapons Miko and Niko. As the lives of relative selves are linked, Jin has two objectives: defend the vulnerable Shin to protect both their lives, and assassinate Kotori to end the ironclad rule of her relative self, Princess Kotoko—his mortal enemy and the killer of his parents. Confronted with this new reality, Shin and Kotori must honestly face their feelings for each other, even if the world as they know it will end tomorrow.

Five years ago, gravity-defying bubbles with mysterious powers rained down upon the earth. After a huge explosion of uncertain origin, Tokyo became ground zero, with the city being enclosed in a gigantic bubble. As a result of this Bubble Fall phenomenon, the metropolis that was once the capital of Japan drowned in a gravity-bending sea; the government declared it a prohibited zone, and the residents abandoned it. Children orphaned by the Bubble Fall now squat illegally in Tokyo, partaking in dangerous parkour team battles across the city's dilapidated buildings. Hibiki—a talented ace in these games with the ability to jump between bubbles—claims he can hear sounds from the Tokyo Tower. Determined to uncover its mysteries, he sets off toward the source, but he falls into the waters below. A strange girl, whom he later nicknames Uta, saves him. But little does Hibiki know that Uta's appearance in his life will reveal the secrets behind the disastrous event that changed their world forever.