There are seven islands in this world.
Each island exists independently of each other. Although they know each other's existence, they cannot find the location of the other. Many people have tried to break this situation, but they have died. The only one who can know the location of these seven islands is the seven-color turtle in the Seven-Color Palace.
There are seven-color turtles in the Seven-Color Palace.
The Seven Colored Turtles are kept in the Seven Colors Palace. There are 7 of them - red, orange, yellow, green, blue and purple. Each turtle recognizes an owner at a time. When the current owner dies, the Seven Colors Palace will put them into the sea, and they will travel to other islands by themselves, find people who are willing to work for them, taste their blood, recognize their owners and bring them back to the Seven Colors Palace.
And this girl with a black ponytail began her wandering and growth when she was 16 years old, and thus met young people who were just as ordinary and extraordinary as she, and who loved wandering.