Yuval Zohar, an architect living in Japan and author of the book Towards a Nude Architecture, has visited more than 120 onsen across the country over fifteen years, documenting each with photographs and sketches. His research led him to Dogo Onsen in Matsuyama, one of Japan's oldest, with a recorded history spanning three thousand years and a main building, the Honkan, completed in 1894 beneath a dramatically sweeping roof more typical of castle or temple architecture. Zohar recounts the onsen's origin legend, in which a wounded egret was healed by the spring, and explains the principle of hadaka no tsukiai, or naked friendship, in which entering the bath dissolves rank and status. He frames the film as a case for why Japan's public bathing spaces, now slowly disappearing, matter as some of the last truly equalizing social spaces left.