The Firehouse Mystery — 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 helping to restore an old firehouse!

The Aldens can't believe that Greenfield's town council wants to demolish the historic firehouse that has stood for over a hundred years. So they decide to try to fix up the building, which houses some valuable firefighting antiques. But someone keeps trying to sabotage their attempts. The Boxcar Children must find out who it is!