First Class Murder — Robin Stevens

A murdered heiress, a missing necklace, and a train full of shifty, unusual, and suspicious characters leaves Daisy and Hazel with a new mystery to solve in this third novel of the Wells & Wong Mystery series.

Hazel Wong and Daisy Wells are taking a vacation across Europe on world-famous passenger train, the Orient Express -- and it's clear that each of their fellow first-class travelers has something to hide. Even more intriguing: There's rumor of a spy in their midst.

Then, during dinner, a bloodcurdling scream comes from inside one of the cabins. When the door is broken down, a passenger is found murdered -- her stunning ruby necklace gone. But the killer has vanished, as if into thin air.

The Wells & Wong Detective Society is ready to crack the case -- but this time, they've got competition.