Guided by instinct, by the otherworldly radiance of the Southern Cross, they head unerringly for their traditional breeding ground where - after a ritual courtship of intricate dances and delicate maneuvering, accompanied by a cacophony of ecstatic song - they will pair off into monogamous couples and mate.

The days grow shorter, the weather ever more bitter. The females remain long enough only to lay a single egg. Once this is accomplished, exhausted by weeks without nourishment, they begin their return journey across the ice-field to the fish-filled seas. The journey is hazardous, and rapacious leopard seals a predatory threat. The male emperors are left behind to guard and hatch the precious eggs, which they cradle at all times on top of their feet. Subjected to  subzero temperatures and the terrible trials of the polar winter, they too face great dangers.

After two long months during which the males eat nothing, the eggs begin to hatch. Once they have emerged into their ghostly white new world, the chicks can not survive for long on their fathers' limited food reserves. If their mothers are late returning from the ocean with food, the newly-hatched young will die.