Secrets on 26th Street — Elizabeth McDavid-Jones

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 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 mother, Susan must discover the secrets their mysterious boarder is hiding.