Kamigami no Itadaki

In a small Nepalese shop, Makoto Fukamachi, photographer for a Japanese expedition to conquer Mt. Everest, stumbles across a camera which may well be that of George Mallory, the celebrated mountain climber who was the first to attempt conquering Everest. Mallory disappeared along with Andrew Irvine during the course of their ascent in 1924, without leaving any indication of whether they reached the summit or not. So, what if it was only on their return trip that they had their fatal accident?