Having solved the mystery of Arch-Aunt Schadenfreude's non-murder and uncovered the location of Grand Uncle Vile's long-lost treasure, Shenanigan Swift might just be in the running for junior detective of the year. But when robbers target Swift House, her sleuthing skills are tested like never before. The trail leads Shenanigan and her sisters to Paris and the Hotel Martinet, home of the estranged French branch of the Swift family. From there, the girls must track down Ouvolpo, a gang of daring thieves who design each of their crimes as audacious pieces of art.