The Clue of the Stone Lantern (Judy Bolton Mysteries)

Judy wonders what has happened to Roberta's father, a sea captain, who writes letters to Roberta. It has been quite some time since Roberta received a letter from Captain Dunn. Roberta suddenly begins to remember snatches of her past-a garden with a stone lantern, flowers, her mother and father. When a strange man and woman show up at the Dobbs home asking about Roberta, Judy instantly dislikes them and wonders about their motive. They claim to be related to Roberta's father and claim that he has died in a shipwreck. After they leave, Judy tries to find Roberta but discovers that Roberta has disappeared. Judy and Peter search for answers to Roberta's strange past, a search that finally leads them to Chicago where they are able to reunite Roberta with her parents.