When Qingran was sorting out her grandmother's belongings, she found a hot bronze key and accidentally opened the secret door in the attic of her old house. Behind the door is a different space with floating luminous islands. The key turns into a talking spirit "Little Copper", telling her that she is a descendant of the "Guardian of the Realm" and needs to retrieve five "star core fragments" scattered on different islands, otherwise the barrier between the two realms will collapse.
