 In this variation on "locked room" mystery, a fickle showgirl (Mida) is killed in a private railway car on a siding in New York s Grand Central Station. Who dunnit? Marc, the rich boy who loved her? Connie, his jilted fiancée? Gangster ex-boyfriend Turk? Private eye Rocky Custer helps untangle the mystery in a series of flashbacks. And the train never even leaves the station!