A gang that uses parties as a cover for robberies victimizes a masquerade party Nancy is attending, so the teenage detective switches identities with a friend to solve the case.
Thirteen-year-old Sammy's penchant for speaking her mind gets her in trouble when she involves herself in the investigation of a robbery at the "seedy" hotel across the street from the seniors' building where she is living with her grandmother.
While visiting Aunt Molly at a fancy downtown hotel, Cam uses her photographic memory to help one of the guests find her stolen luggage and pet cat, and to catch the thief.
In 1887 twelve-year-old Eliza, disguised as a boy and traveling towards Colorado in search of her missing father, falls in with a Gentleman Outlaw and joins him in his illegal schemes.