Gerry Conway didn’t really write “arcs;” he wrote a soap opera with story beats that tended to hit hard at the end of each issue (cliffhangers). But these three issues run together—they feature Sue returning to Reed, with Franklin, only to be taken (along with nanny Agatha Harkness) by Annihilus of the Negative Zone, who wants to use Franklin’s cosmic power as a food source. In the process, Reed goes crazy and Medusa hits him on the head with a wrench. Not sure why cold cocking a guy made out of rubber has any effect, but whatever.
The Annihilus part of the story ends with Reed shooting Franklin with a gun so that the kid doesn’t explode and get his cosmic power all over everyone.
Medusa is sympathetic in that she dresses sexy and lures Reed to a class reunion. This is what I mean about Gerry Conway writing every character as if s/he is a narcissistic, unsympathetic jerk.