It's the greatest natural spectacle on Earth...as it has never been filmed before. As over a million wildebeest take their annual 3,000 km journey across the vast Serengeti plains and Kenya's Masai Mara, they are stealth-filmed by secret spy-cameras that have been disguised to look like dragonflies, animal skulls, tortoise, even piles of dung. These secret cameras follow the fortunes of one calf among the countless herd as he takes his first steps, faces his first deadly perils, encounters dust-storms and a caustic soda lake and arrives for the perilous crossing of the Mara river. Here crocodiles pick-off stragglers, hippos become carnivorous and the river's sheer walls become deathtraps. The result is a film full of awe-inspiring action, high-octane drama and even some tender and amusing moments as the wildebeest, stalked by hyenas, leopards, jackals, cheetahs and crocodiles, undertake a trek that is fraught with danger.