This is probably one of the first Quarry Hall books I ever wrote, maybe 15 years ago, before I even had the name, Quarry Hall. This is before I knew that Joan and Nikki were sisters, or all the backstory of some of the other characters, when Elizabeth was referred to as "Mother" by all the girls and -- get this! -- they wore rings to identify them to other "agents" of their organization and had fish tattoos on their hands and other silliness and secret agent-ish gimicks.
Whew! This is why you want to think a loooooooong time about a series before you start writing, and especially before you get the books published, because when you establish something as a characteristic or key element of a series, you're kind of stuck with it!
NIKKI'S TEST releases next week from Desert Breeze Publishing. You'll get to see the cover art next week, and for about six weeks I'll be posting excerpts from the book every three or four days. Then in late March/April we'll return to the pattern of featuring one book each week, until we get through the whole series.
Right now, though, a book trailer with thumbnails of each book in the entire series.
For your edification and temptation -- QUARRY HALL.