When Cora Kimball got her new auto for her birthday she had no idea what adventures would start for her and her brother Jack. Where did Ed’s money and bonds disappear? Were they misplaced or were they stolen and lost forever. Did the conceited Sid Wilcox have something to do with the missing money, with the help of Ida Giles? And what did the obnoxious Lem Gildy have to do with it all? Join Cora and her friends in this mystery and adventure of The Motor Girls. (Summary by Lucy Burgoyne)