1532. Esteban, age 12 is a foundling from Barcelona, with a mysterious power of ordering the Sun to appear, for which he is called "Child of the Sun." Upon the death of his adoptive father, Esteban learns he was rescued as a baby from a sinking ship in the ocean. The mysterious medallion that Esteban wears since ever has a trace somewhere in the New World, probably coming from the Mysterious Cities of Gold. Esteban leaves Spain to find his parents and find out who he is. On the way he meets Zia, an Inca girl who was kidnapped from her people years back and has exactly the same medallion as him. Later on, they are joined by Tao, a young Galapagos robinson, the last descendant of the Empire of Heva, an Empire said to have built the Cities of Gold. Following Coyolite, the shining star represented on their medallions, the three children travel through the unexplored New World, searching for the Cities of Gold, believing that this way is leading them to their lost parents.

Under the capital city of Tokyo, Japan, there exists a large, vast, and unknown world known as Underground. There, people known as Elemental Users exist; people who have the ability to control the elements: Fire, Water, Lightning, Magnetism, Freeze, etc. Meet Rumina Asagi and his best friend Ginnosuke Isuzu, two average high school freshmen who reside in Tokyo. When they meet Gravity User, Chelsea Rorec, and the Miko of Life, Ruri Sarasa, their whole lives change into one big adventure.

Taka (technically Tamahome) and Miaka are now happily married and only six months before their new family would be born, but an obsessed girl named Mayo would do anything to make Taka hers. She enters the world of the Four Gods, determined to win Taka's heart and be the new priestess.

Astro Boy appears to be a normal, playful kid, yet he is a robot capable of both flying and incredible strength. Living with his parents in a small town where humans and robots coexist, he has many friends thanks to his cheerful nature. Eager to learn and try new things, Astro and his companions often embark on exciting adventures. But their explorations are met with unexpected troubles when the wicked criminal Hamegg—joined by his accomplices Gora, a pink gorilla robot, and Professor Flau—interferes with their endeavors. As the little robot boy and his group bravely face challenges, their efforts become part of a journey to discover the world's values and wonders.