Answer:
According to the Oxford English Dictionary, a madrigal is a type of song which was popular in the 16th and 17th centuries. Thet are arranged for several voices and are typically sung unaccompanied.
The Madrigals are also a group of characters who appear in the 39 Clues, which is a series of adventure books aimed at children. They are accompanied by collectors' cards and an online game.
Madrigals is a branch feared by 4 other branches known as the Thomas, Lucian, Janus, and Ekats. Why they are feared? no one knows. but, I do. Im 110% sure that the reason Madrigals are feared is because they know ANYTHING about any branch. They are also welcomed into any branch as they please. That is why they are feared. The other branches are scared that the Madrigals are going to take valuable information and give it to other branches OR find the 39 clues before their own branch. They are feared, and yes, they are aloud in as they please, but if your a Madrigal, your gaurenteed to be stopped by any other branches and killed. so BE AWARE.. and always remember.... TRUST NO ONE :)
Amy and Dan Cahill are Madrigals. It says in bk. 7