One warm night four children stood in front of a bakery. No one knew them. No one knew where they had come from. A super-special mystery for the Boxcar Children! Henry, Jessie, Violet, and Benny used to live alone in a boxcar. Now they have a home with their grandfather, and they are exploring an old house in Michigan! When the Aldens arrive at the mansion, they can't wait to start looking through all the rooms. They find an old diary that tells that a diamond and pearl ring is hidden in the house. The only way to find the ring is to solve a riddle written in the diary. But someone has already found the ring -- and sold it! Who could be responsible? The Boxcar Children must find out!