Next Door Spy by Karla von Bengtson

5.20

Ten-year old Agathe-Christine, or simply AC, prefers to be on her own. AC fancy mysteries, and from the basement in the building, where she has just moved in, she has established a small detective bureau. AC´s first mystery appears to be simple to solve, but before long AC finds herself involved in a much more complicated affair, than she could have ever foreseen.