Tabu movie plot

Aurora, an elderly Spanish woman, lives with her housekeeper. Their neighbor was a man named Pilar. Pilar wants to do something good in his lifetime, whether people approve of it or not. But she always does the wrong thing. So, she decided to spend all of her meager savings in the Estoril casino. Later, when Aurora dies, Pila discovers a secret of the old lady: a letter she wrote to an old lover. Pila decides to send the letter to Aurora's lover. This letter brings out the second part of the film - a love story that takes place in colonial Africa   .