Phryne Fisher, her sister Beth and her faithful maid, Dot, take a trip to an amusement park with Phryne's two daughters Ruth and Jane. But in the dusty dark Ghost Train, a mummified bullet-studded corpse falls to the ground in front of them. Digging to the bottom of this long-standing mystery takes her to the country town of Castlemaine where it soon becomes obvious that someone is trying to muzzle her investigations. Meanwhile, Phryne's lover Lin Chung has his own mystery to solve.