High school science-whiz Makoto Mizuhara is working on his newest project in preparation for the school festival, alongside his best friend Nanami Jinnai. Nanami's brother and Makoto's lifelong rival, the unscrupulous student council president Katsuhiko Jinnai, is under scrutiny for mishandling the school festival planning and is convinced that Makoto is plotting to steal his position. One night, as Makoto and Nanami are taking a break with their teacher Masamichi Fujisawa, Jinnai sneaks into the science lab and sabotages Makoto's device, which suddenly opens a portal that flings all four of them into another world! Upon arrival, Makoto is immediately attacked by a horde of giant bug monsters. While running from them, he comes across Fujisawa and a girl named Rune Venus. After Fujisawa fights off the monsters, a group of dignitaries arrives, looking for Rune, their princess. They inform Makoto and Fujisawa that they are in a world called El-Hazard and take them back to the palace of Roshtaria, their kingdom. Though her advisors are suspicious of the newcomers, Rune decrees that they are to be treated as guests and quickly befriends Makoto. Unaware that Nanami and Jinnai are in this world as well, Makoto gets to work trying to figure out a way back to Earth.

In the distant future, humanity has been driven to near-extinction by giant beasts known as Klaxosaurs, forcing the surviving humans to take refuge in massive fortress cities called Plantations. Children raised here are trained to pilot giant mechas known as FranXX—the only weapons known to be effective against the Klaxosaurs—in boy-girl pairs. Bred for the sole purpose of piloting these machines, these children know nothing of the outside world and are only able to prove their existence by defending their race. Hiro, an aspiring FranXX pilot, has lost his motivation and self-confidence after failing an aptitude test. Skipping out on his class' graduation ceremony, Hiro retreats to a forest lake, where he encounters a mysterious girl with two horns growing out of her head. She introduces herself by her codename Zero Two, which is known to belong to an infamous FranXX pilot known as the "Partner Killer." Before Hiro can digest the encounter, the Plantation is rocked by a sudden Klaxosaur attack. Zero Two engages the creature in her FranXX, but it is heavily damaged in the skirmish and crashes near Hiro. Finding her partner dead, Zero Two invites Hiro to pilot the mecha with her, and the duo easily defeats the Klaxosaur in the ensuing fight. With a new partner by his side, Hiro has been given a chance at redemption for his past failures, but at what cost? [Written by MAL Rewrite]

Amu Hinamori is a student at Seiyo Elementary, where she has a reputation for being "cool and spicy"; however, her real personality is that of an extremely shy and easily intimidated girl. One night Amu makes a wish that she would have the courage to be reborn as her "would-be" self. The next morning Amu finds three brightly colored eggs—red, blue, and green—in her bed. Each egg eventually hatches into a Guardian Character: Ran, Miki, and Su. Guardian Characters are angel-like beings that aid a person into becoming their "would-be" selves and fulfill the person's dreams. The Guardian Characters accomplish this by giving encouragement and advice, but they can also temporarily change a person's personality and abilities. With the Guardian Characters, Amu's life becomes much more complex as she now struggles to deal with her new personalities and the Seiyo Elementary Guardians—a student council group where each member has their own Guardian Character—who recruits Amu to search for and seal the X eggs and X Characters, corrupted forms of people's dreams.

It is a world replete with dragons and Jushiki sorcerers. Jushiki is a devastatingly powerful formula that can alter the laws of physics, capable of creating enormous TNT explosives or poisonous gas through plasma and nuclear fusion. A down-on-his-luck sorcerer named Gayus joins forces with the beautiful but cruel Jushiki practitioner, Gigina, as bounty hunters pursuing dragons. Then one day, they are presented with an odd request: to serve as security guards for a grand festival put on by Mouldeen, the ruler of their kingdom. It is then that a mysterious serial killing of Jushiki sorcerers begins. (Source: TBS Global Business)