Conceptually speaking, this movie branches off the earlier Winged Migration, and might have been named Ambulatory Migration. The storyline is more complicated this time, so there's more work for a narrator. Morgan Freeman supplies the voice-over for the USA version and does an excellent job.
Small bands of would-be parents waddle and slide about 70 miles to the camp. Like other migratory birds, emperor penguins have built-in GPS, so only a few get lost, though some perish from exhaustion.
Upon arrival at camp, the moms- and dads-to-be pair off. The gals outnumber the guys and sometimes fight for a date -- the guys seem to enjoy this part. There's no rule about finding the same spouse as last year, and some don't find significant others -- better luck next year.
There's not much to do in Antarctica, and relationships are very important. The penguins bond strongly (to call it a marriage would not be out of place), which is fortunate, as the coming ordeal will test both parents severely.
After the egg is laid, mom keeps it safely pinched between her feet and her belly for a little while, but she's starving and so the pair rehearses kicking the egg over to dad. Getting it right is essential: if the egg is exposed to brutal cold for more than a minute or two, it'll freeze solid. Inexperienced teams sometimes flub the hand-off. Either way, mom heads for the ocean, 70 miles distant.
While the mom's are off to fill up (eating for two), the also-hungry dads keep themselves warm against the bitter polar winds by huddling. After some weeks of shuddering cold, junior hatches. Dad and junior bond, but dad is hungry -- he coughs up one meal for junior, but mom better be back soon (she'll be able to cough up a lot more).
When the moms finally get back, the dads turn over custody and head for the ocean, as now it's their turn to feed. The moms do child care for awhile, but take off a little before the dads return, because the chicks need a preview of life on their own -- a sobering experience. Dad gets back shortly before junior totally freaks (unless junior has been eaten by a predator).
This process of parents switching off, with some family time in between, goes on for several months, but with increasing frequency as the ice is melting and the ocean is getting closer. By the time the young penguins are ready for reorientation, the ocean is pretty much adjacent to camp.
Finally, having done some initial training, the parents disperse, having discharged themselves responsibly. The young adult penguins hang out in high school a little longer, then dive in for five years of college in the deep blue sea, only to emerge as full-fledged adults, ready to start their own trek to the camp ground. And so it goes. There's a lot of conformity here, few lifestyle options.
I was glad for the outtakes during the credits, showing the human camera teams at work. I dislike documentaries which pretend camera teams don't exist -- my main beef with that IMAX film Everest, which never shows the camera team at critical moments (even a few stills would have been an improvement).