When Bellhaven's Historical Society gala turns deadly, antique shop owner Penny Reed has three hours to catch a killer before the case walks out the door.

The evening's toast is meant to unveil a rare eighteenth-century chronometer and the treasurer's biggest announcement of the year. Instead, he's found dead in the gallery, his own pocket watch shattered at the exact moment of the attack, and the priceless piece is missing.

With the gala's guests locked inside and a county crime unit hours away, Detective Mike Russell gives Penny until the deadline to prove her apprentice didn't do it. But every suspect left in the building, from a jilted collector to a debt-ridden nephew to the society's own trusted president, has something to hide.

Penny has until the clocks strike the hour to find out whose alibi doesn't survive the math.