Hang Son Ðoòng which translates as “mountain river cave”, is located in the Phong Nha-K Bàng National Park in Qung Bình Province in Vietnam. The national park is also a UNESCO world heritage site.
First found in 1990 by a local farmer, it wasn’t explored until 2009 when a British expedition team rigged ropes and descended down. Many people have described Son Ðoòng as a lost world. It has its own lake, jungle and even a unique weather system. In 2014 plans were announced to build a cable car into Son Ðoòng.
With many arguing that this would destroy the cave’s delicate eco-system and the local community divided over the benefits this development would bring, the film follows those caught up in the unfolding events. The documentary also uses the narrative as a lens through which to investigate related themes such as the challenges of modern day exploration, environmental conservation & sustainability, and the perils of operating as an activist in a country such as Vietnam where freedom of speech is severely curtailed.