The Mystery at the Alamo — Gertrude Chandler Warner

One warm night four children stood in front of a bakery. No one knew them. No one knew where they had come from.

Henry, Jessie, Violet, and Benny used to live alone in a boxcar. Now they have a home with their grandfather, and they are visiting the Alamo.

The Boxcar Children arrive at the Alamo to find that a movie is being made there -- and they are going to be in it. But then things start to go wrong on the movie set, and a priceless ring from the Alamo museum disappears. Are the two things connected? It is up to the Boxcar Children to solve this new puzzle!