We've come to the last renumbered issue of Fantastic Four before it reverts to the continuation of the aggregate issues with next month's ominously named "The End is FourEver" with #642. Reed is captured, Franklin's being experimented upon, while Sue, Ben and Johnny start investigating the cause of all this.
spoilers:end of spoilers
Cully, Reed's captor, calling himself the Quiet Man, reveals his infatuation with Sue, his regret at Reed reaching her first, his scientific work in the background and his nanite-based facial reconctruction tech that enabled him to pose as different persons in different situations, including prosecutor Tolivar. He also insinuated that he's behind at least some of the attacks on the FF over the years. Franklin is the key to him to finally reveal himself; and Onome tries to reach out to Bentley to do something; but while Bentley shows signs of concerns for Franklin, he relents and tells the FF children to hold their tongue. In the meantime, HR Captain America frees HR Hawkeye from police custody as Spider-Man and Johnny arrive too late to intervene. And, Sue and Ben's probing around the Baxter Building is interrupted by Sam Wilson Captain America, Hulk, Namor, and SHIELD agents, witch Jim Hammond at the two's side.
So we've got another battle on our hands, but sans knowing what started it and why.