Ruthie and Jack are still basking in the glow of having discovered an album of lost photographs from a famous artist, an album which turned up in the Thorne Rooms when they used a magic key to shrink down and get into them. When they meet Dora Pomeroy, a decorator who is studying the rooms, they realize that articles are missing, just as art is being stolen from famous collections around Chicago. While investigating, the two travel back to 1937 Paris and meet a Jewish girl. When they realize that her family will be in danger from the Nazis, they try to get back and warn her, only to find that their key has been stolen! They find another way in, and start to realize that the thief is someone they know-- and they may have helped the stealing begin! The two work to put things in the Thorne Rooms to rights, and once again emerge victorious.
Strengths: Love the inclusion of real miniature rooms, time travel, and a good mystery.
Weaknesses: Figured out too early who the thief was! The first book has been a steady but somewhat slow circulator.