On her birthday, Mery receives the worst news: her husband died in a confusing road accident. Meanwhile, Román, the boyfriend of Mery's teenage daughter, Celina, was involved in the accident. The processes of grief and how to deal with guilt as a teenager come together to tell the story of survival in "The Last Birthday."

After midnight, Ángeles and her son Miguel knock on the door of Mercedes's house. The house is located in the mountains a few kilometers from the highway. Mercedes's life is neglected due to her advanced age. Ángeles' humanity, Mercedes's hope of one day seeing her children again, and the secret Miguel keeps make this film a story that will touch the heart.