When Hiyori⁠—a young girl whose deceased father taught her the joys of fishing⁠—headed out to sea for some alone time, she never thought that she would encounter another girl there. After a while, this girl⁠—named Koharu⁠—and her end up fishing and cooking together, and they get to know each other a bit in the meantime. During their brief time together Koharu finds out that the reason Hiyori went out to sea that day was because she's hesitant towards meeting her new step family that same evening. But what a coincidence! Koharu is also meeting her new family tonight! "No. It can't be a coincidence..." Follow these two 'sisters' and their new life together!

In the world of Gift, the bowels of the planet hide a highly sought after crystalline substance known as Giftium. A young boy on Gift named Sougo Amagi inherited his interest in Giftium from his mother, a researcher. As an inhabitant of Garden Indigo, a small and prosperous miner's town, Sougo has many opportunities to forage and collect rare crystals that can only be found there. However, the most exciting treasure that Sougo discovers is not a crystal, but a person. After being pulled into a school quarrel, he plummets into the deep caverns of an old mine. There, in the abysmal depths of the earth, Felia—an enigmatic girl with red eyes and blue hair—emerges from a large crystal. Through this strange first encounter, bonds of friendship are formed between Felia and Sougo. But Felia is being pursued by a secret organization that aims to use her powers for their own benefit, and Sougo and his friends must help her, all while discovering the true nature of this girl from the crystal. [Written by MAL Rewrite]

Daisuke Higashida is a serious first-year student at Higashizaka High School. He lives a peaceful everyday life even though he is not satisfied with the family who doesn't laugh at all and makes him tired. However, his father's company goes bankrupt one day, and he can no longer afford allowances, cellphone bills, and commuter tickets. When his father orders him to take up a part-time job, Daisuke decides to work at a nearby family restaurant in order to avoid traveling 15 kilometers to school by bicycle.

Cool-headed and rational, Koujirou Shindou is a government official and master negotiator with a well-earned reputation. While departing on a business trip, a giant cube materializes and his plane is taken undamaged into the mysterious, indestructible structure. As Japanese authorities attempt to identify the cube's properties and origins, Shindou encounters an otherworldly entity known as Yaha-kui zaShunina, who materializes in the form of a human man. He assures Shindou that the passengers are not in any danger and requests help in negotiations with the human world. Hailing from a higher dimensional universe known as Novo, Yaha-kui zaShunina is able to transfer information between Novo and Shindou's universe through a cube called Kado. Despite having these unfathomable abilities, he does not appear hostile. Instead, he announces that he has come to this world with only one intention: to "advance" humanity—starting with Japan. [Written by MAL Rewrite]