It was published in 1954 by Grosset & Dunlap and written by Charles S. Strong under the house pseudonym Carolyn Keene.

[1] Nancy meets Helene and Henri Fontaine, refugees from Centrovia who run a dancing school in River Heights.

Nancy and her friends pursue the trail relentlessly, even though danger lurks around every corner.

When she briefly separated from Ned, Renee grabs her and puts her in the back of his car, bound and gagged.

But Nancy's quick wit finally enables her to solve this intriguing and intricate mystery.