Kahlo's sister, Cristina, moves in with the two at their San Ángel studio home to work as Rivera's assistant. Soon afterward, Kahlo discovers that Rivera and Cristina are having an affair. She leaves him, and subsequently sinks into alcoholism after moving back to her family's Coyoacán home. The couple reunite during a "Día de los Muertos" celebration where he asks her to welcome and house Leon Trotsky, who has been granted political asylum in Mexico. During an excursion to Teotihuacan, Trotsky expresses his love for Kahlo's work and they begin an affair. Soon, Trotsky's wife learns of the affair, which forces the couple to leave the safety of Kahlo's home.