The Disappearance Cipher — M.L. Buchman / Matthew Lieber Buchman

Dilya is now the leader of the dog pack. But when one of the nation's top spies disappears, how can Dilya find her? Or should she?Dilya Stevenson, nanny and dog sitter to the First Family, always trusts herself, her dog, and her mentor—first, second, and third. Everyone else stands outside that circle.But when her retired-spymaster mentor disappears, Dilya and the First Dog can't find her alone. To save her mentor's future, she must reconnect with her own past.Originally published as a five-story series: The Race Begins, The Library Trail, The Catalog Message, The Railway Code, The Two-Dog Solution.