Bridwell, Gill and Sparling send the Secret Six into North Korea in issue 4 (Oct/Nov 68).
This story gives the focus to King Savage, and we get to learn more about the period during the Korean War when he was captured and tortured. The Secret Six have been sent on a mission there to retrieve a general who had fallen into disgrace and been imprisoned.
It's probably my least favourite issue, just because it's so fairly straightforward. The big twist consists of the fact that the man they are going to bring back to the west is the same man who tortured and broke King Savage. Is that really a surprise?
By this point in the run it has become clear that the missions tend to be linked personally to members of the Secret Six. There is some emotional drama for King Savage, facing his tormentor, and the added plus that the guy does not want to be rescued by him.
The general is brought to the west, and so now responsible for disgracing his own country. One can also note that the US government is becoming increasingly aware of Mockingbird's operations, and none too keen on having this wild card running around with his own agenda. That basically clues the reader in that Mockingbird must have his own government connections - and of the Six, only Durant does.