On a rainy afternoon, a male high school student awakens freezing on the streets with no memory of how he got there. His classmate and crush, Karen Inukai, finds him and takes him back to her home where, to his surprise, she starts to undress. She seems intent on bathing with him, though he has no idea why. When she holds him once more, he catches a glimpse of himself in the mirror—discovering that he has turned into a dog! Inukai adopts the puppy and names him Pochita. Now, he must adjust to life as a dog and figure out how to get out of this strange predicament. But while he mulls over an escape plan, Pochita sees a whole new side to Inukai that he never saw at school.

Tricked into assassinating his own prospective father-in-law, righteous samurai Raizou Kurima is overwhelmed with guilt. In order to reclaim his honor, Raizou swears vengeance on the lord who gave him those misleading orders. In his pursuit, he is aided by self-proclaimed merchant-of-all-trades Yuuen Usui, who is actually one of the Revengers—assassins who seek justice for the wronged and dispense bloody revenge on their behalf. Tragedy seems destined to follow Raizou as he becomes increasingly intertwined with members of the Revengers. As he begins working as a vigilante alongside them, the complicated web between the corrupt Japanese political elite, the unscrupulous Europeans, and the Revengers gradually reveals itself. The more entangled he becomes in these affairs, the more Raizou realizes that justice is as deceptive as the honor that he sought to redeem.

Humanity is facing extinction. In a snow-covered world where water has become scarce, the last habitable lands are located at the feet of gigantic Orbital Trees scattered about the desolated Earth. According to a legend, there exists a sage who knows the secret to producing abundant quantities of water to save mankind. Liliha, the princess of Atland, uses an organic hot-air balloon to climb to the top of an Orbital Tree in hopes of meeting her country's savior. Once she reaches the Canopy—an area that appears to be an infinite window of transparent ice—she meets Kaina, one of the last men alive on the Canopy. However, she can not find the man she was looking for. Unable to return by herself to her country, the princess finds a helping hand in Kaina, who is eager to explore the surface world that he thought was empty. As Kaina learns about the war against Liliha's country, the antagonistic technologically advanced nation Valghan, and other perils of the surface, he realizes that his escorting mission will prove more difficult than he imagined.

Princess Anisphia "Anis" Wynn Palletia has always dreamed of flying through the sky, even though the people of her kingdom consider it a silly ambition. Also at odds with her goal is the fact that Anis is incapable of using magic despite her noble status. Refusing to give up so easily, she renounces her right to the throne, and focuses on developing "magicology" by combining various resources with knowledge from her previous life on Earth. Due to Anis' nature, responsibility for the kingdom's future is passed onto her younger brother, Algard. Pushed into a political marriage with Euphyllia Magenta, a girl he hardly knows, Algard rebels by spending more time with a commoner girl than his fiancée. After Euphyllia tries to intervene, Algard publicly calls off their marriage and denounces his ex-fiancée as a bully. After crashing into the banquet where Algard makes the announcement, Anis rescues Euphyllia on the flying broom she is testing. She decides to make Euphyllia her assistant, which the other girl reluctantly agrees to. Although their partnership appears random at first, Anis has an ulterior motive for wanting Euphyllia's company.