Four mathematicians are imprisoned in a shrinking room; with the walls closing in, they must try anything to escape this fatal puzzle.

The film tells the true story of Elisa Sánchez Loriga and Marcela Gracia Ibeas, two women in 1901 Spain who fell deeply in love. To overcome societal and legal barriers to their relationship, Elisa assumes a male identity, enabling the pair to marry in secret. Their daring act makes them the first recorded same-sex couple to marry in Spain, but their love is tested as they face relentless persecution and sacrifice.