. Tonight, on an all-new "20/20" -- Many are familiar with the blockbuster movie, "American sniper," and how an American hero was lost. Chris Kyle, surviving the most dangerous war Zones, only to be... See More
. Tonight, on an all-new "20/20" -- Many are familiar with the blockbuster movie, "American sniper," and how an American hero was lost. Chris Kyle, surviving the most dangerous war Zones, only to be killed on home soil at the hands of a fellow veteran. That somebody would shoot him in the back -- he didn't have any chance. But tonight, the hero we didn't know. The sniper's wife. The American wife. Taya Kyle, reluctantly drawn into the spotlight. My life lately has been, the volume turned up all the way. I'm here. Your family is here. Your children have no father. I love to serve my country. Tonight, she's inviting us in. Is it difficult coming back now? I don't know. Once we get to the place that it all -- I don't know how I'll feel. Reporter: A journey with taya Kyle back to the darkest day in her love story with her husband. On an emotional drive into the north Texas hill country, winding our way over creek beds, through prairies of bluebonnets, miles of range bounded by barbed wire. We always felt like it was one of the best places on Earth honestly. Reporter: It's serene. It is. Reporter: I mean, it's horrible what happened, period, but in such a beautiful, peaceful area. "20/20" cameras allowed access for the first time to the scene of the crime that shocked America. The gun range where Chris Kyle lost his life. As a way of comforting myself in some ways I just thought, well at least it was maybe peaceful and he didn't see it coming. Reporter: A brave taya Kyle, about to confront the ghost of an unimaginable loss. You ready to do this? I'm good. Good evening, I'm robin Roberts. Later tonight, we'll be back at the place where her life changed forever. But first, the story you never knew until now. So many of you saw the movie, but that's only half the story. In her new book, "American wife" taya Kyle gives an unflinching look at their life. Reporter: This is American sniper Chris Kyle as you've never seen him. Not in a Hollywood movie but in a home movie. One of many his wife, taya Kyle, is sharing exclusively tonight with "20/20." You might not like everything, but it's for a reason. Faith was very important to Chris, too. Reporter: The blessing of a new child. It's scenes like these that inspired taya to write her new book, "American wife," where she tells her story of love and loss with Chris. There is so much more to him. It was my chance to share some of that side, too, because I think he, I think he's earned it. Reporter: For taya, Chris was her unlikely soul mate, her cowboy in shining armor. He just had this softness and this tenderness. I continue to look back and be in awe of how he managed it all so well, honestly. Reporter: When you open the book, four words jump out -- love, war, faith, renewal. Why those four words? Love certainly is always a key thing for me, it always has been, probably always will be. And the war taught me a lot. I mean, it brought the greatest pain in our marriage, but it also brought greater strength. It's been a lifelong journey, but definitely it was more clear with my time with Chris how I had to rely on my faith and then, you know, renewal is a -- it's a constant process. Reporter: Four words, four powerful forces shaping their lives from the earliest years. Born in Texas, Chris drifts from job to job as a ranch hand and professional rodeo competitor. He finally finds purpose in the Navy S.E.A.L.S. During the grueling training program he befriends fellow Navy S.E.A.L. Marcus Luttrell, famous in his own right as the subject of the film, "Lone survivor." Are mike and Danny really dead? I don't know. People die all the time in our training. Not -- I'm not talking about combat. Just talking about training. I mean blood and sweat every day. Reporter: Chris not only survives. He thrives, showing immense talent as a sharpshooter, earning his S.E.A.L. Trident. He's stationed in southern California where, as the movie shows, he meets taya. She's working as pharmaceutical sales rep and, as she says in her book, depressed after a series of bad relationships and an unsure future praying for a man with a good heart. You know, I wanted to be really independent, even though I knew I kind of needed somebody. Reporter: Her prayers would be answered during a night out at a bar of all places. The chance meeting between taya and Chris started off on a pretty rocky note, as seen in the film "American sniper." Okay, how true was that first meeting? So true. I mean, I drank a little too much and he held my hair back while I, you know, let it all back out. But -- Reporter: Great first impression, taya. Yeah, right, I know. It's such a gentle, tender exchange. And I feel like that was so incredibly true with Chris. And that was what was so intriguing. So yeah -- and it was funny. Reporter: So, not exactly love at first sight? Or was it? I mean we're in a bar, you know, and he was so genuine and had a depth to him and this really hot body with a cute face. Reporter: When he told you what it was that he does for a living, I believe you said you didn't want to marry a S.E.A.L. Right. Where are you going? I said I'd never marry one. My faith is different now, because I think god has a plan. And you can really hard to think you know what's going to happen, but I don't think any of us do. And no, it wasn't my plan, but I'm so glad I did. Reporter: So when did you know in your heart that he was the one? It was just little by little. He was so nice. Real. I mean, just so nice and supportive. He made me feel like he was excited to talk to me, to see me, and he was just this simple, fun, deep person. Reporter: On March 16th, 2002, Chris and taya wed on a sunny California day. Exchanging inscribed wedding bands, taya wrote on Chris' ring "My life, my love." And he wrote "All of me" on her ring. But from day one Chris is torn between love for his country and love for his family. They have to cut their honeymoon short, because Chris is called up for duty. Marcus Luttrell's wife, Melanie, is a dear family friend. I mean they loved each other passionately. I think there was a lot of -- sometimes ups and downs through different events. But they're going to stay strong together afterwards. Reporter: The struggle between family and military service would continue to test their marriage. But when he is home, Chris is committed to their growing family -- a son who Chris immediately nicknamed bubba. Give me a hug? Reporter: And a daughter nicknamed angel, that commitment undeniable. It's these stolen moments that taya treasures most. What kind of father was he? Amazing. I truly don't think there's a better example of what a father should be than him. I can barely think of a day, you know, there may have been less than ten in our whole lives that I remember him not laughing with those kids, no matter what kind of day he had. Reporter: Here's a perfect day -- shot by taya. Chris roughhousing "Navy S.E.A.L. Style" with bubba who can't get enough. And a game they called "Poke the bear" which inspired the filmmakers. Taya's camera captures more than the fun times. She also records poignant, reflective moments like this. Listen closely as Chris talks to his son bubba the night before his third deployment. You know this isn't really for you right now. Come here, bubba. We'll read two more and then you can go to bed. This is so later, when I'm gone you can look at the tape. Reporter: I know when he said, when I'm gone -- he was referring to deployment. But he is gone. And this can be played. What are your emotions, and your children, when you see this? I know there was a part of him that also was referring to being gone for good. And that was always a possibility, when it came down to, would he be okay with dying on the battlefield? Absolutely. But I think in the moments where you're holding your kid and thinking about not being there with them, that's when the pain, you know, comes in. Reporter: And there was plenty of pain for Chris, and for taya. When we come back, trouble in the marriage and what the home movies would reveal about a family in crisis. What's this year going to bring for you? Sickness, misery, bankruptcy. Springtime.
This transcript has been automatically generated and may not be 100% accurate.