The Case of the Frozen Hearts — Emma Kennedy

Wilma Tenderfoot, a tiny, brash, and determined ten-year-old orphan, dreams of becoming a world-famous detective so she can find out who her parents are. When she is hired out to crotchety Mrs. Waldock, Wilma discovers that her next-door neighbor is the renowned detective Theodore P. Goodman, and he has a new case. Set on becoming his apprentice, Wilma makes deductions, follows leads, and scouts out suspects, all with the help of her beagle, Pickle. She's sure she'll win the famous detective over and crack the case - as soon as Pickle stops eating all the clues.

"Nothing and nobody stops Wilma Tenderfoot!" (If she does say so herself.)