Secrets on 26th Street: American Girl History Mysteries

Secondhand, paperback, read condition.

Synopsis: It's 1914. Susan O'Neal's widowed mother takes in a boarder to help pay the rent--an Englishwoman named Bea. As Susan helps Bea unpack, she glimpses a letter with the words must be kept a secret for now. Susan forgets about the letter for weeks... until Mum disappears. Suddenly Susan realizes how little they know about Bea--and she becomes sure Bea is somehow involved in Mum's disappearance. To find her other, Susan muust discover the secrets their mysterious boarder is hiding.