The PCs are in the small Himalayan kingdom of Nepal, there to investigate suspicious Chinese activity. The agency (or whomever) wants to know what Red China is so interested in. The suggested cover for the PCs would be as adventurers, there to mountain climb or perhaps humanitarian relief workers.
NPC foil: the PCs will run into an agent of a friendly agency or government (tailored to the campaign), posing as an International Red Cross doctor. The NPC will be acting very suspiciously and generally acting as a Red Herring. This NPC may be a good back-up should the party need help in the later parts of the adventure. He/She is looking for survivors of the previous mission sent to Nepal (see below).
The story: The Red Chinese are looking for a group of mixed Tibetan rebels and special-forces troops. These are the survivors of a mission team send to investigate the Chinese presence in Tibet. This previous mission team had found out about an illegal Chinese uranium mine (or some such) but been scattered before they could report in. The Red Cross doctor/agent is understandably curious as to what happened to the team and probably suspicious the PCs had something to do with it.
The Major threat: A half-Korean, half-Chinese Ministry of State Security agent with a personal grudge against both India and the Western Allies. His mother was slain by UN forces in Korea in the early 50s. His father died in border fights with India. For campaigns set later, you could replace Korea with Vietnam.
This could be used as part of a larger “new” Cold War campaign between India and China.