Fermat's Room (2007) on Netflix

Plot summary

A stranger calling himself Fermat invites four people to work on the greatest enigma, each under the alias of a historical mathematician. To accept, they must solve a puzzle; the answer earns them a code name and instructions to travel alone, without a phone. Galois, Hilbert, Pascal and Oliva gather at a riverbank, follow coordinates from a PDA to an abandoned warehouse, and find an elegant parlor with a table set for five. Fermat joins them for dinner, then takes a call about his daughter, who he says lies in a coma at a hospital, and leaves. The door is blocked. A puzzle appears on the screen with one minute to answer, and the walls of the room begin to move.