Parker basically undoes what he did in the previous issue–the Namor and Namora romance, at least the impending nuptials–as fast as he can. There are some backstory developments and some supporting cast developments, but it’s really just an excellent exercise in drama. Parker’s undoing of this romance, he does it in one issue instead of twelve (the modern story-arc is so much different than even fifteen years ago), is superior because of his storytelling ability.
It’s hard to imagine the narrative going any differently–especially with all that undersea life for Bob to get naughty, touchy-feely thoughts about–and there’s where Parker truly succeeds. Even though it’s a fast resolution, which retcons Namor and Namora’s entire existence, Parker sells it.
The issue is apparently the last one with the “Dark Reign” tag on the front, which Parker clearly references in the issue, with Jimmy discussing it.