Life in the ocean began as single cells and, over billions of years, became the vast range of marine creatures alive today, and this IMAX production traces that arc using footage shot for giant screens. The camera moves from simple organisms toward increasingly complex forms, using specific sea creatures as stand-ins for major steps in the evolution of multicellular life, the kind of transition textbooks describe in a sentence and this film spends its runtime showing. The visuals carry most of the argument: coral reefs, open water, and deep-sea life shot in the high-resolution format built for large-format theaters. The film does not stop at deep time. It turns to the present-day ocean and the pressures on it now, climate change and overfishing among them, and asks what continued disruption means for ecosystems that took billions of years to assemble. The pairing of evolutionary history with contemporary threat gives the film its shape, using the same species first to illustrate ancient adaptation and then to show what is currently at stake.