This story begins in the Great Rift Valley, where the continent is tearing itself apart and being reborn. 

 

The plains in the shadow of the rift, the Serengeti are threaded with the paths of the millions on the move in a constant burning search for fresh grass. 

 

Every year, more than a million wildebeest and 200,000 zebras must chase the seasonal rains in a 300-mile loop around Tanzania and Kenya. 

 

But here in the Serengeti, they pause for an avalanche of young, the most migration-ready newborns on earth. The wildebeest have a scant three weeks to deliver half a million calves, who have only minutes to get up on their feet, because the predators and the scavengers have the migration clock etched in their genes as well. 

 

For them, this is a weak and movable feast. For the newborns, it's "get going" or "get eaten".