The Fugitives!

From what we know of Quicksilver's and the Scarlet Witch's time in the Brotherhood of Evil Mutants, the siblings were not at all happy with being obligated to serve the group's leader, Magneto, in order to repay a debt incurred when he saved their lives from European villagers who harbored superstitious fears toward their mutant abilities. The situation was at least tolerable for Quicksilver, however, with his animus toward humans evident even then; though while technically bound by the same debt that Wanda owed Magneto, he mostly remained to protect his sister from the detestable behavior of their fellow members, Mastermind and the Toad, as well as any possible mistreatment of Wanda on the part of the ruthless Magneto.

Even so, when the opportunity arises for he and his sister to free themselves of Magneto's yoke, Pietro is insistent that they take advantage of it. Yet there are complications--with Wanda, of all people, having reservations as to what course of action to take, if any.

At this point in time, the Avengers were using Tony Stark's 5th Avenue townhouse as a weekly meeting place (and temporary H.Q. when necessary), so the Fantastic Four were indeed the only heroes whose famous address was a dependable avenue for callers.

Unfortunately, this pair's reputation as villains, deserved or not, has preceded them.

And so, with the Torch and the Thing predisposed to deal with any dangerous mutants on sight, the way is paved for a conflict which, if better handled on both sides, might have been avoided.  At any rate, it's a bizarre matchup, to be sure--but which duo holds the edge?

It seems that in these early days, the FF, as well, aren't yet set up with a system in place to deal with the occasional visitor off the street who hasn't called ahead. Instead, they appear to depend upon the security detail of the Baxter Building to be their Jarvis in terms of greeting or otherwise dealing with those who wish to see the FF for whatever reason. Failing that, of course, their private elevator is geared to only respond to those wearing a special belt signal--though no doubt a simple thing for the Scarlet Witch's hex to overcome.

No doubt any number of villains will be gratified to learn that the stairwell leading directly to the FF is freely available to all.

Yet Pietro is fortunate that Reed isn't in the building right now--the guy thinks of everything.

Yet if Pietro and Wanda are hoping to arrive to pleasantries, they're in for an unpleasant surprise, given that their rap sheet is the only thing on the minds of the Thing and the Torch as they turn to face their unannounced and intrusive visitors.

For now, at least, the unconscious Wanda is out of the fight (and there will be a fight, as if you had to guess), which provides us with a look at how a man who moves faster than the eye can follow (even in close quarters) can make a decent showing against two members of the Fantastic Four. It's also doubly impressive when you consider that someone who makes lightning-fast attacks must also plan his moves against his opponent(s) at equally fast speed before executing them--which essentially means that by the time either Johnny or Ben decide on a course of action, Pietro is literally ten steps ahead of them.

But Pietro wages his battle in a suite, not a chamber--and soon enough, the Torch devises a way to compensate for his foe's tactics by nullifying Pietro's speed advantage with an improvised cell formed with his own abilities. As for the Thing, he's delighted to take the handoff of the baton and greet Quicksilver as his jailer, with all due alacrity.

Yet the coup de grâce the Thing aches to deliver is foiled by the awakening Scarlet Witch, who sizes up the situation and acts to defend her brother. And in her own way, her approach turns out to be as gentle as the Thing had planned his own to be regarding Quicksilver.

No, I don't know how Quicksilver managed to remain unaffected by a torrential gust of storm that bowls over even the Thing. I suppose the fact that he "runs like the wind" should be taken beyond mere metaphor.

Regardless, the incident helps to put an end to hostilities on both sides, and both Pietro and Wanda depart--regrettably convinced that mutants cannot hope to find peace among humans, and that their only option for now is to return to their place in the Brotherhood.

For what it's worth--and as we've already seen--the decision of Wanda and her brother here doesn't necessarily bind them to Magneto's side indefinitely; simply that if and when they do decide to leave the Brotherhood, they're on their own.

As for the Torch believing that the FF's leader would just let this pair depart without insisting they remain and explain their situation, now that both sides have taken a breath--Johnny, have you met Reed Richards?