The Dinosaur 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 a dinosaur mystery to solve!

The four Aldens like visiting the large old museum owned by their grandfather's friend. But then Jessie sees a huge, scary shadow moving in the room where dinosaur skeletons are on display. And bones from the enormous Tyrannosaurus rex disappear!

The Aldens must find the missing bones and solve the mystery before an exhibit is scheduled to open -- or there might not be a dinosaur exhibit at all!