You are in the grasslands of North America, 15,000 years ago.

You were foraging near the edge of a dense woodland, when the forest went unnaturally silent. The air held a musty, musky scent.

About 50 feet away, partly obscured by shadows, a massive cat stepped onto the prairie. It was heavy, with a short tail and limbs far more robust than a modern lion. The most terrifying feature wasn't the size, but the two massive, curved daggers extending from its upper jaw, shining with a slight dampness. As it lowered its head, revealing the wide mouth that allowed those sabers to do their work, it gave a low grumble.

The Smilodon wasn't stalking in a sprint; it was analyzing you with intelligent, focused eyes…