An octopus slithers into a narrow crack near the shore; we see its eye up close; blowing water propels it through water. It feeds on a crab. In spring it’s time to mate. A male grabs a female; he inserts his third arm in her respiratory cavity. We watch another pair: a larger female is the aggressor here. Mating is repeated over hours and days. With high magnification, we see many sperm; she releases strings of fertilized eggs that hang from the roof of a nest. She guards it for a month, fanning the strings to circulate water for oxygen and cleanliness. We watch the eggs up close develop at 1,400 times nature’s rate. Then they’re born and propel away.