Sarah Masters Buckey

When a famous archaeologist has the priceless jewel he is carrying to London aboard a cruise ship stolen, Samantha and Nellie help him narrow down the suspects

Marie-Grace Gardner, a doctor's daughter who has just returned to her native New Orleans in 1853, makes friends with Cécile Rey, whose prosperous family are free people of color, and is persuaded to change places with her at separate Mardi Gras balls.

"Marie-Grace can't wait to begin her journey up the Mississippi River with her father. The steamboat they're traveling on is the biggest and fanciest boat Marie-Grace has ever seen. It's crowded with all sorts of interesting passengers, including Wilhelmina Newman, a girl her age. Wilhelmina is traveling alone, and she's carrying a secret in one of her trunks--clues to hidden Gold Rush treasure. Marie-Grace and Wilhelmina have to unravel the clues...