One fateful summer, a group of elementary school kids set adrift on an abandoned apartment building must look within themselves to find a way back home.

Middle-aged businessman Ryoma is reincarnated in a magical world by three gods. He's a child again, and he spends his days with his tamed slimes.

The story is set in the distant future. The land is ruined, and humanity establishes the mobile fort city Plantation. Pilots produced inside Plantation live in Mistilteinn, also know as the "birdcage." Children live there knowing nothing of the outside world or the freedom of the sky. Their lives consist of battling to carry out missions. Their enemies are mysterious giant lifeforms known as Kyouryuu, and the children pilot robots called Franxx to face off against them. For the children, riding the Franxx proves their existence. A boy named Hiro is called Code:016, and he was once known as a prodigy. However, he has fallen behind, and his existence seems unnecessary. Not piloting a Franxx is the same as ceasing to exist. One day, a mysterious girl known as "Zero Two" appears before him. Two horns grow out of her head.

Ousai Academy was originally an all-girls high school. Due to the declining birth rates in recent years, it was converted into a co-ed school. The first year male students would find themselves surrounded by girls and unfortunately, Tsuda Takatoshi is one of them. What's worse, he gets scolded on his first day by the student council president Shino Amakusa, which did not give a good first impression of him. Tsuda also meets the other student council members while getting scolded, and in the end, he gets late for class. As an apology for ruining his morning, Shino lets him join the student council for various of "reasons" and he accepts it, or rather, he's forced to accept. Thus begins his days as Tsuda soon realizes that he's the only normal student in Ousai Academy...

Bell Cranell is a rookie adventurer and the sole member of his dirt-poor guild founded by the petite goddess Hestia. Adventurers come from far and wide looking to strike it big in the massive labyrinth known as Dungeon, located beneath the city of Orario. Bell is more interested in picking up girls than Dungeon-crawling, but his reality check comes sooner than expected. Saved from a brush with death by the beautiful, renowned adventurer Aiz Wallenstein, Bell falls head-over-heels and sets his sights on winning her heart, but she's not the only woman he's caught the attention of, for better of worse.

Ousai Academy is a former all-girls private high school which has recently been integrated for both genders. Takatoshi Tsuda is pushed into becoming the vice-president of the student council, where he is the lone male member surrounded by three beautiful girls.

Assigned on a mission to capture Mukade, a missing-nin, Naruto Uzumaki sets out for the once glorious historic ruins of "Ouran", where he pursues and corners the rouge ninja. Mukade's goal is revealed to be a dormant leyline within the ruins; he unleashes the power of the leyline, causing a light to envelop Naruto, sending him into the past, 20 years before the series began. When Naruto awakens, he comes into contact with the Fourth Hokage, Minato Namikaze.