Agatha Christie's trusted housekeeper, Phyllida Bright, has become an amateur sleuth in her own right. When a party game leads to murder, she decides to crash the investigation.

While her famous employer is happily back home at Mallowan Hall, wrestling with her Belgian detective's dilemma on board the Orient Express, Phyllida is finding her local renown as a sleuth has put her in high demand. A distraught Vera Rollingbroke suspects her husband of infidelity and has invited Phyllida to a dinner party to observe his behavior, particularly in regard to one Geneva Blastwick.

What she does observe at the party is that Geneva craves attention, in contrast to her shy sister Ethel. Geneva introduces a game called Two Truths and a Lie, and one of her questionable statements is that she once witnessed a murder. At this bold claim, the guests react with disbelief and pepper her with questions. Geneva remains cagey, withholding details, but insists this is not her lie.

The next morning Phyllida learns poor Ethel was purposely run down by a motorcar the previous night while inexplicably walking home alone from the party. She fears Geneva may have been the target, which means someone at the party is a killer--twice over. A chilling thought. With Geneva in potential danger--and Inspector Cork proceeding ponderously as usual--Phyllida takes it upon herself to unmask the killer. With two murders to solve, she will need to grill Geneva and the guests as well as re-examine any past sudden deaths or disappearances. And if she's smart, she'll look twice before crossing the road . . .