There is a mysterious island in the sea. There is an academy on the island that specializes in magic, called Deep Sea Academy. There are barriers around the college, and only people in the college and students enrolled in the college can enter and exit at will; three days there are equal to one day in the real world. However, the strange thing is that Deep Sea College only enrolls 100 students every year, and classes only take place during the summer vacation.
This year, Deep Sea College has started recruiting students again, and another exciting summer vacation has begun.