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WRITERS ON WRITING: How I Wrote '21 Grams'

Guillermo Arriaga takes you on the inside journey of writing his film '21 Grams,' from idea to completion.

GUILLERMO ARRIAGA is a screenwriter and producer, known for Babel (2006), 21 Grams (2003) and Amores Perros (2000), and a critically praised novelist. Follow Guillermo on Twitter @G_Arriaga.

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 PHOTO: Jim Sheldon

PHOTO: Jim Sheldon


I was driving to my birthday party, 15, maybe 14, years ago and I was late. I didn’t know what kind of excuse I was going to give Maru, my wife. She and my friends were waiting for me. Suddenly, on one side of the road I saw ambulances and patrol cars. I stopped to find out what was going on. The university where I taught was in the outskirts of the city, and that was the road most of my students rode on their way home. I just wanted to make sure nobody I knew was hurt. There was a man, 30, maybe 35 years old, lying on the dirt—dead. A car had run over him. A police officer took out his wallet. He found his name on an ID and a photograph of the man with a woman and two kids, all smiling. Now that same smiling man was lying dead on the road in the dark night. Two kids and a woman were waiting for him. The event obsessed me.

I thought: What if I ran over a man and his two daughters? What if I arrived late to my birthday party because I had killed a family? What would I say to my wife? How would I feel? That accident became the genesis of 21 Grams.

I told this idea to director Alejandro González Iñárritu when I met him. There was no story, no plot. Just that: an idea. But we both thought there was something more in there.


I had just finished the screenplay of Amores Perros, and I was in Spain promoting the Spanish edition of A Sweet Scent of Death, my second novel. I went with my wife to Sevilla and; on the way back, on the AVE train, I fell asleep. Suddenly, coming from nowhere, I dreamt the story of 21 Grams: A guy runs over a father and his young daughters. Another man, terminally ill, receives the heart of the father and goes to look for the widow. The man who killed this family feels so guilty he runs away from everything. That was what I dreamt, and I trusted my instinct. That night I called Alejandro and woke him up. It was 4 a.m. in Mexico City. “Negro (that is his nickname), I got the story, I got it,” I told him. “What is it about?” he asked. I told him about my dream. “Okay, write it. I’m with you,” he told me.


I have a daughter, Mariana, and a son, Santiago. When Santiago was four or five years old, he asked me, “If I die, will you ever smile again? Will you ever play again?” I didn’t know how to answer him. Mari Carmen, my sister-in-law, had lost her two-year-old son when he fell into a swimming pool. When they found him, it was too late. She and her husband suffered the terrible pain of losing a child. But life went on; they had other kids, and three years later she smiled and played again. My son didn’t understand how that could happen, how someone could ever smile again after such a terrible loss.

Once I took Mariana and Santiago to the set of Amores Perros. I wanted them to see the scene that came after the car accident. Three weeks earlier they had watched—without my permission—the film IT, about a murderer clown. They had been having nightmares every night, so I wanted them to see that movies are not real, that they are just a representation of reality and not reality itself. I wanted my children to see the fake blood, the fake fire, Gael García and Goya Toledo acting, not actually dying.

 Sean Penn and Naomi Watts

Sean Penn and Naomi Watts

The scene was brutal. Those who watched the film know what I am talking about. In
the middle of the scene, Mariana, seven years old then, asked me if we could go
for a walk. I was excited and I didn’t want to leave the set, but she begged. She was
shocked and she wanted to get away, so we started walking, holding hands. Suddenly, she stopped and asked me, “Why are they making such a horrible film?”

“My love,” I answered, “I wrote this film.”

“Why did you write that?”

“Because that’s what I have inside my heart.”

She stared at me for a while. “What a horrible heart you must have,” she said.

I wrote that film as a response to Santiago’s question, to tell him that no matter how terrible the death of a loved one was, life has a much bigger power. That life has a healing power in itself. That life, in the end, goes on.

I also wrote that film to show Mariana what I have inside my heart—maybe it is horrible, maybe not. She’ll be able to tell when she’s old enough to see these two films, and when she can read my novels. But, horrible or not, my stories are always written from the heart.


I gave Alejandro one of the first drafts of the screenplay. It had another title. He suggested 21 Grams. He had read about the concept in an old French novel. I had read about it in some magazine. I agreed, 21 Grams was the perfect title. Alejandro always finds titles that say much more than what is implied. He did so with Amores Perros and also with 21 Grams. He has the virtue of emotional synthesis.

I really don’t know if losing 21 grams at the exact moment of death is a scientific fact. I used it as a metaphor of the weight a dead person has over those who remain alive.There are loved ones who, after their death, remain with us all of our lives. We miss them every single day, and, of course, life goes on, but their absence follows us forever.


I am a huge fan of William Faulkner’s literature. Also of Juan Rulfo. Both of them always find ways to tell each story differently. That is their great lesson: Every story has a particular way it has to be told.

I strived to find the right structure for 21 Grams. When I started writing the story, it had a different structure. It was like a cube that showed another side of the story at every turn. But it wasn’t working.

One night I was going through some old manuscripts. I found an unfinished novel that I intended to write when I was 24. The novel began with a dying man who thinks: “So this is death’s waiting room, these ridiculous tubes, these needles swelling my arms,” and then it went back and forth with scenes of his past and present life. There I found the clue for the structure: Tell the story as we tell our own daily life stories. We never tell them in a straight line. We jump from one point to the other. I also went back to an old short story of mine, “In Peace.” It also jumped back and forth in time. So I started putting different scenes together with no time connection between one and the other. I jumped from one scene in the present to one in the past to one in the future to one in the past, and so on. My challenge was trying to make it work narratively—to have enough dramatic questions to keep the readers interested and allow them to construct a parallel story in their minds, filling in on their own the huge gaps of information that the structure left out.

I gave the first 20 pages to my father and to Maru. They are both my best critics and tough readers. They were hooked. “What’s next?” both asked. At least the narrative was working.

We all know that one scene has a meaning by itself and a completely different one when it is linked to a scene before and a scene after. I wanted to go beyond the conventional, so I went for symbolic choices. I started writing scenes in a contrasting order, so that the structure itself would help change the audience’s perception of the story, making it much more emotional. That was my main goal: Make the story emotional, not just intellectual. I wanted the screenplay to challenge the heart as well as the mind. I’m not interested in creating jigsaw puzzles. I like structures that help the audience get involved in the emotion of the story, so they can smell, touch, see, feel. That’s it: feel.

The next step was to build the structure carefully, trying to have large narrative ellipses, but with an emotional continuum. So, in order to achieve that, I needed to create a balance within the scenes, a kind of narrative yin yang. I combined passive scenes with active ones; scenes that posed questions with scenes that answered them. Sometimes in one scene I presented the facts in a certain way, and then, in another scene, I changed those facts completely. I was looking for a way to make the audience be much more participative—to have a constant dialogue with the film, to create and recreate the story. There were themes that could improve this involvement: love, death, life, hate, revenge, forgiveness. So I tried to use scenes with contrasting emotional themes; for example, scenes of love and then scenes of revenge.

 Naomi Watts in 21 Grams

Naomi Watts in 21 Grams

Then there was light. I am obsessed with light, and I think it can completely change the way a film is seen. Light, in films, has a great emotional power. I intended to create an emotional path through light. In the first 35 pages, I tried to have predominately day scenes in order to communicate that there was some light in the life of these characters. Then, when the accident is revealed, I wrote mainly night scenes. I remember a biblical passage that says, “and then the night came,” a metaphor for when they took Jesus prisoner, when everything in his life became dark. So I used night scenes for the next 35 pages as a metaphor of death, a metaphor for the abyss the characters were going to confront. On the final 40 pages, I used mostly afternoon and evening scenes: The characters’ lives are going through light and darkness. I tried to have the climax happen during the night and then have the montage of the last scenes with different lighting.

The reason for this final montage goes back to 18 years ago when I had a terrible car accident. I was sleeping in the back seat when the car suddenly rolled over a deep cliff. I woke up in the midst of shattering windows and metal breaking. Since then I have become obsessed with what happens just before an accident. How were things a minute before? Were people smiling or celebrating or angry? Did they have everything in their lives solved? Did they ask for forgiveness that day? That was my intention on the final montage: to put the immediate moment before the accident together with the final consequences. And how, after all the pain the characters had endured, in the end they find hope.


When I wrote 21 Grams, I wanted to explore the way a human being can fulfill his need of hope—not the easy way but through the hell that some people live. How could these people, submerged in a deep abyss, overcome their pain, their fears, their guilt, their desire for revenge and find hope again? Where in the darkest places can someone find the hidden road toward hope?

My three characters come from personal hells: Jack (Benicio Del Toro) comes from the hell of jail and child abuse. Cristina (Naomi Watts) comes from the hell of drug addiction and Paul (Sean Penn) from the hell of very bad health. When they think they have overcome their personal hells and reached heaven—Jack through Jesus, Cristina through her family, Paul through a new heart—circumstances send them to a deeper hell, an obscure abyss where there seems to be no escape. They struggle, fight and suffer, but they end up finding hope. They discover that, beyond death and desolation, life has an enormous power—a power that allows us to move on, to continue living. The characters of 21 Grams have a final reconciliation with life, an acceptance of pain and fragility and a desire to move on.

I truly believe 21 Grams is a film of hope and a story of love. Love is what allows these characters to find hope. It is Paul’s sacrifice of love that saves Jack and Cristina from their pain, guilt and desire for revenge. It is love that makes Cristina understand there is a purpose in life; and through his love for his family, Jack finds himself again. For me, love and hope always go together.

We are maybe the only species that builds its identity through the ones around us. We are only through the others. When we lose our loved ones, we lose our identity. The loss of someone means undeniably the loss of a part of ourselves. Each relationship marks us in a definitive way. We can only rebuild ourselves by relating again with others, loving again and not forgetting our lost ones. For me, love and hope are the themes in 21 Grams.


My screenwriting teachers always told me I had to know all about my characters, to know even the brand of underwear they wear. I completely disagree. I like to know very little about my characters, almost nothing. I want to allow them to come to life by their own means. I like being surprised by them. And I hate research. I never do any research. I like to imagine, to feel how the character would react being in his position. I only investigate when the screenplay is finished, so I can polish the details.

I develop my characters through three main sources: observation, imagination and experience. I created Paul under my own experience: I had a viral infection in my pericardium, nothing serious, but at that time I was boxing and playing basketball daily, and the pericardium was so swollen that it strangled my heart. The doctor prescribed bed rest for three months. He said that in some rare cases, the inner muscle of the heart gets infected; and when that happens, it is necessary to have a heart transplant. So I started imagining the way a man should feel if he received someone else’s heart. I thought that I would definitely look out for the family of the one who rescued my life, as Paul does with Cristina.

Cristina represents my deepest fear: to lose someone I love in a violent way. She goes through an experience that I know would devastate me. An unbearable one. Cristina was born the same day my daughter was born. She’s a drug addict. Never in my life had I drank alcohol, tried drugs or smoked. Never. But I am obsessive, and I know what it means to be a prisoner of something inside of me. I know about having a terrible need for something. I have also seen friends dive into self destruction through alcohol and drugs.

Jack was the character that fascinated me the most. He represents a world I hardly understand: fanatical religion. He is a man in utmost pain who throws himself into the first thing that really gives him hope: religion. He’s so limited and so primitive that his religious experience is chaotic, confusing and rigid. I had a friend, an atheist, who got married to a born-again Christian. His wife was so religiously sick that she thought anyone out of her sect was touched by the devil, so she restrained her husband and his contact with the rest of the world. Of course, I lost my friend, who became a disciplined follower. A lot of this friend’s experience is in the character of Jack.

I remember the exact day I thought of Jack’s character. I was driving through the central Mexican desert. My wife and my kids were sleeping, and it was raining on the horizon. Suddenly, we crossed beside an abandoned car without doors and windows. In that moment, the image of a car thief came to my mind. I woke up my wife and told her: My character is going to be a born-again-Christian car thief, a man who will have pain all over him and who tries to overcome it through Jesus. I named him Jack, the English name for Santiago, my son’s name. I named his wife Marianne, the English name for Mariana, my daughter’s name.


Screenwriter Guillermo Arriaga on the set of 21 Grams

Screenwriter Guillermo Arriaga on the set of 21 Grams

This is my second collaboration with Alejandro González Iñárritu, director of 21 Grams. The first one was Amores Perros, also a film of love. You cannot imagine how proud I am to work with him: generous, funny, intelligent—a man of huge talent. He puts everything he has in his heart into his directing. He is committed to his work with a passion rarely seen. He cares for every detail in the film. When he arrives on the set, he has been working that scene for weeks. He doesn’t leave anything to luck.

With Alejandro I had the most beautiful arguments you can imagine. I’m a very stubborn guy. He’s twice that. But he never imposes his point of view. He always tries to convince. Sometimes I want to kill him. Not because he was wrong, but because he was right, and I hated to accept it. My screenplay owes a lot to him, and I thank him.


I wrote this article before the film was released. I’m happy, nervous, excited and very anxious. It is one thing to try to achieve something and another to actually achieve that something. All my work acquires its meaning before an audience. It has nothing to do with concessions, but with the desire to establish a dialogue with the person who sits in the dark to see the film.

My strongest desire is that 21 Grams can deeply touch the people who see it. The process of writing for film only ends when someone sees your work on a screen and then, that same night, just before falling asleep, he closes his eyes and thinks about it.

Originally published in Script Magazine January/February 2004



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