Open Water is about 61-year-old open-water swimmer Marilyn Korzekwa's attempt to be the first person to ever complete a crossing of the eastern end of Lake Superior. It uses experimental underwater photography techniques and immersive sound design to convey the subjective experience of swimming non-stop through a night and a day. It chronicles the changing moods of the lake over the course of the swim as Marilyn and her small support crew weather the waves and numbing cold.