The film shows how, in 2010, Foster began free-diving in a cold underwater kelp forest at a remote location in False Bay, near Cape Town, South Africa. The location was near Simon's Town on the Cape Penninsula which is exposed to the cold Benguela Current of the Atlantic Ocean.

He started to document his experiences and, in time, met a curious young octopus that captured his attention. He decided to keep visiting her, tracking her movements every day for a year to win the animal’s trust. They form a bond where she plays with Foster and allows him into her world to see how she sleeps, lives, and eats. In the film, Foster describes the impact of his relationship with the octopus on his life.