"The truth is never dreadful, it is only interesting."

When the distinguished scientist Sir Claude Amory suspects that the revolutionary formula he has invented for a powerful explosive may be stolen, he calls upon Hercule Poirot to spend the weekend at his country house to ensure that the Belgian detective will deliver it safely and unharmed to the Ministry of Defense of Great Britain on Monday. However, the weekend will prove disastrous, both for the formula and its creator. Hercule Poirot, with the help of Captain Hastings, will have to untangle a web of family feuds, old loves, and suspicious foreigners in order to find the murderer and prevent ultimate destruction.