High school student Sōsuke Kudō has a peculiar dream in which he finds himself in a white void facing a blackboard that asks what single item he would bring to a deserted island. While his classmates give ordinary answers, Sōsuke answers crafting ability. He awakens to find that he, along with his childhood friend and other classmates, has been transferred to an uninhabited island in another world. True to his answer, he has been granted a powerful crafting ability that allows him to create virtually anything he needs.

Unlike what might be a desperate survival scenario, Sōsuke finds the harsh island life surprisingly easy to overcome thanks to his crafting powers. He quickly establishes a comfortable existence and soon finds himself surrounded by a growing group of beautiful girls from his class, including his kuudere childhood friend, a gal who is kind to otaku, a pure and refined young lady, and a diligent class president. What follows is a slow, relaxed life on the island where Sōsuke uses his abilities not just to survive but to thrive, creating everything from basic shelter and food to modern conveniences like appliances and infrastructure.

The narrative includes a Start Dash Special Event in which the group can earn the right to return to their original world as a reward. During exploration for a new base location, the party encounters a gentle maid who is recruited by a summoner classmate and also comes across a solitary, gloomy girl who joins them. As the story progresses, Sōsuke befriends a new teacher who cares about his students and encounters a teasing black gyaru. The island itself becomes more dangerous when a water-dwelling monster called Avank is added following one of the mysterious blackboard questions that appear regularly. Eventually, a girl with barrier abilities named Serina also becomes part of the group. Throughout these developments, Sōsuke continues to deepen his relationships with the girls, who openly express their affection and desire for intimacy with him.