Transcript for In the Center of a Lion Feeding Frenzy
You've no doubt heard of the shark tank. But have you ever heard of a lion box? Tonight, we're going inside one smack in the middle of a feeding frenzy. All for a surprising reason. Here's glory Ya Riviera. Stop. I can see lions. Reporter: These three lions, all brothers, reign supreme in this game preserve. Just come across right here. Reporter: Following their every move, Boone smith. They're going to make a go at the hippos here. When those Lio locked on the hippos, it was lightning fast. Reporter: We're here in south afri Africa, to put himself squarely on their turf. Man versus lion, capturing it all on camera. I wanted to be a member of the pride. See that point of view. I've been tracking three of them all morning. Reporter: He makes his living tracking and trapping big cats all over the world. He's a throwback to a far more wild era. A fourth-generation tracker. He's tagged everything from cougars in Idaho to snow leopards. There's an addiction to the adrenaline. The adventure, what's over the next hill, down the next valley. Reporter: We set out with him to get a taste of that feeling. It's dawn, and it's very early. He gets to work, tracking the queen lioness. He knows she's had three new cubs, but no one has seen them. And ranger Greg is with us, with a magnum just in case. We're going to go very slowly. Reporter: But danger finds us fast. Oh, my god, there's a rhino right there. A rare white rhino. And they're blocking our path. And they pass, and they manage to spot the mama lioness. That one just broke the bushes. Reporter: They're barely visible with our binoculars. What do you think? I think we better go look. Reporter: Are the cubs still alive? We're going to go a little bit higher. So we can see her, but she may not be able to see us. We're going to tiptoe. I've got eyes on her. Reporter: Once we're in position, a clear view through the brush. She's looking right at us. The cub is right underneath here. Reporter: What's it like to see this? How unusual is it? We're pretty fortunate to see this. Reporter: That's as close as we get. But he's taking it to a whole new level. You have a wife and kids. What is her reaction? She gave up on me a long time ago. Reporter: She's the one person that needs to give the world's best big cat tracker the okay. I stay in the car. Can you bring that lion to me? Reporter: His latest project, put himself inside a custom-made box during a feeding frenzy. I was like, what are you talking about? Well, it could be really dangerous if you don't do it right. Reporter: It had to be able to withstand an attack from a group of hungry lions. It broke. It's half the thickness. Now, the real deal. I'm feeling better about that. I think this is safe and good to go. Time to head to Africa. Here we come. The box will put me inches away from the lions while they feed. Reporter: And so, after months of planning with the box in place, there's just one task left. We've just locked ourselves in the box. Two lions are very close to us. I can hear lions roaring. Reporter: It takes just 20 minutes. Four lions converge on the box. Three brothers plus a new female. Do you hear that? Scratching the glass. They're right there. You can hear your heart just going. Not so much out of fear, but just excitement. There's a 500-pound lion right next to me. One of the brothers. Get ready. It's going to get wild. Reporter: Inside the box, Boone has a front-row view of the rapidly-changing dynamics of the brothers. They had worked together to support each other. Now, a female is in the mix. That changes the dynamic. Reporter: They fend off their brother's attempt to feed. There's a point, are they going to challenge their older brother? Wh who's going to win the right to breed? Oh! We're getting crushed against the tree here. Reporter: Do you know anyone else that has had this experience? Lions have the confidence, they let us view them. Just one inch away, I can put my hand. It's a rare and magical moment. Reporter: A unique view, not for the faint of heart. Big cat week kicks off with the premier of man versus lion on Friday, November 28th on nat geo wild.
This transcript has been automatically generated and may not be 100% accurate.