In a remote part of New Zealand’s South Island, "Harry” and his fellow underwater obsessives set out to dive deeper than anyone ever has before. Controversially, they plan to use hydrogen as a breathing gas – its explosive nature adding to the many hazards the close-knit team faces. As the 2019 Australian of the Year prepares to confront the dark waters and life-threatening cold, he questions the costs of his passion. In this SXSW-selected nailbiter, Peedom and co-director Alex Barry capture the tension, euphoria and mateship of this endeavour using Harris’s own vertigo-inducing cave footage, along with DOP Ben Dowie’s striking above-ground imagery and a compelling score by multi-award-winner Antony Partos.