'Forbidden Mountains' describes the unforgettable journey of two women who embark on the ultimate adventure: to sneak into Tibet from northern Pakistan and cross the country via the South Route, largely unknown to outsiders. Tibet's occupying force - China - has devised unique punishments for travellers who defy its no-go policy, but Vivien and Joanne decide it's worth the risks to visit one of the world's most mysterious and holy lands.