In the Kingdom of Yamauchi, people have the ability to transform into three-legged crows known as yatagarasu. While the men plot over daily governance, women compete for the hand of Wakamiya, the crown prince who was selected as the Kinu, the servant to the Mountain God. Four young women arrive at the court to join the competition, including one named Asebi. While the kind and innocent Asebi sticks out like a sore thumb compared to the other women, the crown prince has to fight for his place in the clan. Despite being born both to a concubine and as a second son, the royal priests still chose Wakamiya to be the Kinu over his older brother. This decision created a rift between the siblings while enraging Wakamiya's stepmother in the process. When Yukiya, one of the teenage sons of the village chief, is sent to the palace to become Wakamiya's new attendant, the prince is not pleased in the slightest. However, Yukiya's presence at the imperial courts is no mere coincidence.

Jougorou Kobato has a habit of inserting himself into other people's problems. After realizing his detective skills are neither wanted nor appreciated, he makes an agreement with his shy friend Yuki Osanai to become ordinary together. Now entering high school, they aim to be perceived as regular people, yet Kobato cannot help but fall back into his deductive ways when faced with everyday mysteries. Unfortunately, mundane occurrences are not all the duo stumbles across. As they go through their school days trying to avoid drawing attention to themselves, Kobato and Osanai at times get caught up in incidents that put their plan of a peaceful, average life at risk.

Duke Fleed is a survivor of the Fleed Planet who is escaped to the Earth, onboard a mysterious "spaceship", where is raised by Dr. Umon as his adoptive son, and known as Daisuke Umon. Years after his arrival, he's faced with the threat of King Vega and his army, who want to conquer the Earth. With his friends Koji and Hikaru (and later his younger sister Maria Grace), Duke decides to fight back using his best weapon - the almighty Grendizer.

Nikola is just a village girl working at the inn...until the day dragons invade, and she meets Haga, a scholar of everything around him. He's a part of an elite society called "Seeker," created to address a series of maladies plaguing their usually peaceful world. But both Nikola and Haga have secrets they hide...ones that will change each other's very existence...