Cowpokes head into a mysterious Mexican valley to head 'em up and move 'em out. But they're not looking for little doggies. They're looking for great big dinosaurs.

James Franciscus stars in this thunderous adventure featuring amazing special effects by Ray Harryhausen [The Beast from 20,000 Fathoms, Clash of the Titans (1981)]. Franciscus plays a Wild West showman who leads his riding and roping crew into the title region, where prehistoric giants still roam. Thanks to Harryhausen wizardry, fantastic creatures lunge, fight and rampage in scene after dazzling scene (including an awesome sequence where the cowboys rope Gwangi, a razor-toothed allosaurus). Saddle up and join the excitement.