Marvel Two-in-One (1974 - 1983 1st Series) #21 (Nov. '76) co-stars Doc Savage and his merry band of associates. Meaning this is one of the two issues in this 100-issue series that didn’t get reprinted in the Essential volumes because Marvel lost the reprint rights to Doc Savage when DC Comics later bought the rights to the character. The other issue not reprinted is #99 (May '83) that features ROM the Spaceknight - another character Marvel can't reprint.
The layout of this issue is nicely done, because at the beginning they have the Thing and Johnny Storm on the left side of each page in the (then) present-day of 1976, and on the right side the reader sees Doc Savage and his men back in 1936. Due to the oft-repeated Marvel time travel plot device, Doc and his men get transported forty years into their future to team up with Ben Grimm and the Human Torch to put a stop to Blacksun, an evil character who dared to tamper with cosmic forces with disastrous results. This is an entertaining story, and if you're not familiar with the Doc Savage pulp fiction character, DC later reprinted the two Marvel series he was featured in - Doc Savage: The Man of Bronze TPB collects Doc Savage (1972) #1 - 8 and Showcase Presents: Doc Savage collects Doc Savage (1975 Marvel Magazine) #1 - 8.