"The Sinister Shadow of... Doomsday!"
The X-Men escape the Factor Three headquarters, but they know that the Mutant Master continues his plan to start World War III. The team splits up to make sure that both the Russians and the US don't launch nuclear missiles to start the war.
"The Spirit of Swami River"
Reprints X-Men (1963) #38 and a 5-page story from Amazing Adult Fantasy #9.