A stranger using the alias "Pierre de Fermat" invites several people to attend a convention of the country's best mathematicians. To accept the invitation, each must solve a math puzzle. Upon receipt of the correct solution, each receives as an alias the name of a famous mathematician or philosopher; they are forbidden to reveal their true identities to the other attendees. Each is instructed to arrive at a specific place and time, alone and without a cell phone, to work on "the greatest enigma".