Mark and Kerry, a brother and sister, are visiting Quebec with their father, who is on a business trip. Their father allows them to explore the city on their own during the day while he works (something that would be unlikely to happen in modern times). The kids enjoy sight-seeing and learning French words and phrases. They even make a new friend in the city, but they are troubled by events at the quaint little inn where they are staying.
On their first day there, Kerry’s coat mysteriously disappears and reappears with some strange messages in the pocket. A boy wants them to take a message to someone in the city. At night, Kerry hears someone crying in the next room. Is the boy being held prisoner at the inn? If so, why? Kerry and Mark are determined to help in any way they can, but time is running out.
The solution to the mystery involves family quarrels, custody issues, and racial tensions. In spite of that, this is actually a very gentle story. In the end, the kids are dependent on the people the mysterious message was intended for to help a troubled, lonely child.
The author describes the atmosphere of Quebec in some detail. The famous landmarks probably haven’t changed much, although I don’t know if all the descriptions are accurate anymore. I also thought it was interesting how the author includes some French phrases and their pronunciations and translations as the kids learn to communicate with French-speaking people in the city.