Grad student Violet Tenet can't believe her good fortune. Thanks to a secret benefactor, she's traveling abroad with only one odd request to fulfill-a weekly telegram addressed to her patron. In exchange, she finds herself exploring Venice's museums, campi, and canals while she learns about a gem-encrusted Carnival mask stolen during the chaos of World War II. The Sebastiano Mask, however, isn't the only mask missing in Venice. Violet's friend, Tom Fielding, reports a Plague Doctor mask has recently vanished as well, and from the very same museum. Even more disturbing, an unidentified woman was found murdered at the scene of both crimes, more than sixty years apart. Soon, Violet realizes the mystery of the two masks is far more complex than she ever imagined, that both she and Tom are involved, and it's all up to her if they are to survive an adventure that takes them from Venice to London to the Scottish Highlands and beyond.