This is a really nice mystery series for children. They are fun, short and easy to read. This case had to do with a woman pretending to be a lost twin.
This one has to do with the mystery of some marked money. Polly and Ruthann helped their friend Officer Greenwood solve the mystery.
Polly and Ruthann help Officer Greenwood solve another case. This time it has to do with two baseball teams that dislike each other.