He visits a pharmacist in Chinatown where Sun Yat delivered his secret materials for forwarding to AXE.
If the mission to destroy the bomb in the Chumbi valley is a success the CIA will support Fan Su's anti-communist Undertong movement.
To prevent him revealing any information that might compromise the mission Carter and Fan Su kill Po-Choy as he is paraded at a Red Guard rally.
Carter and Fan Su escape from Shanghai with the assistance of a CIA-operated Civil Air Transport plane which takes them deep into China yet still 500 miles from the Chumbi valley.
In the Chinese hinterland, Fan Su's family friend, a local warlord named General Teng Fa, provides shelter and armed guides while they wait for a CIA plane from Sikkim to take them to the Chumbi valley.
Carter leaves Fan Su alone guarding their camp and infiltrates the secret tunnel excavation where he plants a small atomic grenade near the unfinished H-bomb assembly.
The bomb is timed to explode 30 minutes after Carter and Fan Su are picked up by helicopter at their pre-arranged landing site.
Carter is picked up by the CIA helicopter and returns to base in Sikkim as the tunnel and bomb are destroyed.