In The Balance (Danger Point)

His first wife died suddenly—and his wealthy new bride may be about to meet a similar fate . . .
 
Former schoolteacher Miss Maud Silver is making her way back to London
when, with a violent shudder of the train, a young woman is thrust into
her compartment. She is beautiful, well dressed, newly married, and
wealthy—which may be about to get her killed.
 
In a state of
shock, Lisle Jerningham explains that she fled her home in a hurry when
she overheard a sinister conversation through the bushes. Her new
husband’s first wife died in an apparent accident, and the resultant
infusion of cash saved his family home. Now, he is broke again—and
trying to engineer a second convenient mishap. Miss Silver is unsure
whether the drama is real or a figment of Lisle’s imagination—but if
this frightened young lady is a target for murder, the killer will have
to deal with the governess-turned-sleuth first.
 
Starring a mature sleuth who “has her place in detective fiction as surely as Lord Peter Wimsey or Hercule Poirot”, In the Balance is a classic British mystery (Manchester Evening News).