In March 1940, John Steinbeck and marine biologist Ed Ricketts sailed the coast of California and Mexico down into the Sea of Cortez, and this film retraces their route through the same shallow waters and tide pools they cataloged. Their stated purpose was scientific, an inventory of the creatures living on the margins of the sea, but their writing kept drifting toward bigger questions: what humanity's relationship to the natural world actually is, and where hope might come from as the planet headed into war. The film follows that same drift, using their own words, including the line about the sea giving them "a feeling of fullness and richness," as a throughline. It also picks up a warning the two men raised decades early, that overfishing would eventually gut this rich water, and sets that against present-day footage of a La Niña bloom, the periodic Pacific cooling that can still trigger a surge of life in the Sea of Cortez. The two timelines, 1940 and now, run side by side throughout.