the bustling Parisian setting, particularly focusing on the café de Périclès, where several characters gather during an evening of card playing. The night takes a dark turn when a scream disrupts the atmosphere, prompting patron Doctor Legris and his companions to investigate an apparent assault outside. Upon discovering an injured man, Raymond Delorge, the arc of mystery begins, compounded by Delorge's unusual reaction to the incident and the presence of a letter he has swallowed. The chapter sets an ominous tone, hinting at underlying secrets and the sinister actions of shadowy figures, capturing the reader's attention with an aura of suspense that promises deeper explorations into these interconnected lives. (This is an automatically generated summary.)