In the dead of night, Lawrence Cavendish awakens the narrator with dire news of his mother, Mrs. Inglethorp, suffering a severe fit. Despite her room being locked from the inside, urgency propels the household into action, trying to access her locked chamber through various routes, all in vain, until a door is forcibly opened. The household discovers Mrs. Inglethorp in agony, writhing from convulsions which subside momentarily only to violently resurge, leaving everyone helpless and distraught.

Amidst this turmoil, the absence of Alfred Inglethorp, Mrs. Inglethorp’s husband, raises suspicion, especially given Mrs. Inglethorp’s strained utterances that seem to implicate him. Dr. Bauerstein, a passing specialist, attempts to aid Mrs. Inglethorp but to no avail; her death seems inevitable as she succumbs, uttering Alfred’s name in what appears to be an accusatory manner. This prompts discussions of potential poisoning, stirring tension and suspicion.

The household, already enveloped in sorrow and confusion, is now faced with the grim prospect of an inquest necessitated by the peculiar circumstances of Mrs. Inglethorp’s demise. Contemplating these events, the narrator proposes engaging his friend, the renowned detective Hercule Poirot, to investigate, suggesting foul play might be at hand. The suggestion is met with resistance, reflecting the prevailing skepticism and the overarching tension surrounding the mysterious tragedy at Styles.