"Here is your pay." Kay is dumbfounded as she watches her host, Alice Janey, give a mysterious witchlike woman some money. Kay later learns that Nanna is Miss Janey's clairvoyant and that Nan revealed the location of Miss Janey's missing luggage. Miss Janey has full confidence in Nanna, since her luggage was indeed found in the exact location described by Nanna, but Kay remains suspicious.

First, Nanna owns the house in which the luggage is found, and second, the valuable contents of the luggage are missing when the luggage is recovered. Kay believes that Nanna is scheming against Miss Janey, but proving it to Miss Janey will be difficult.

How Kay learns the truth about Nanna and helps Miss Janey with an important chemical experiment makes for a thrilling story.