"Water is an intermediary force between the stars and us," gushes Patricio Guzmán in this searching, sweeping doc, a spiritual sequel to his 2010 epic Nostalgia for the Light. That meditative lulu found intuitive links between two vital quests: that of astronomers searching the heavens for the history of our universe, and that of the women of Chile still seeking the truth about family members who were "disappeared" during the Pinochet dictatorship. Just like the ancients staring up at the vault of the sky, Guzmán sketched profound new shapes in the patterns he studied. In The Pearl Button he attempts the same, with less stellar results: Here, he surveys Chile's almost 3,000-mile coastline, especially that "archipelago of rain" that is Patagonia, where ice edges against islands at the world's tail-end. The photography is wondrous, with the highlight a trip up against and almost under a berg the blue of flavored ice — it hulks and it creaks, indomitable even as it's doomed.
Over such footage, Guzmán muses about the possibility of water on other planets, on how it's the key to life. He asks, of some other planet he's imagining, "Might it have trees for large canoes?" That's in reference to Guzmán's other interest here, more vanished people, populations of seagoing natives from long ago -- their stories are told in interview and old photographs -- as well as political prisoners thrown, at Pinochet's behest, into the Pacific. The voiceover is lyric, the oceanscapes majestic, the anthropology fascinating, and the connections more quizzical and uncertain than in Nostalgia for the Light. This time you have to look harder to follow him.