A pair of explorers enters the Seti Gorge in the Himalayas to film an area where none has ever dared to venture. Extremely narrow at little over ten meters, but tremendously deep at over 200, the origins of the gorge are shrouded in mystery. Numerous waterfalls tumble into its abyss, and even for the experienced Japanese adventurers, the descent using a single rope tests their courage. Freezing winter temperatures, torrents of water – a gripping journey unfolds on camera. The latest research reveals the geological saga that created this massive gorge.