This is a six-page backup story featuring the Fantastic Four.
The Fantastic Four are just standing around in the Baxter Building when an inter-dimensional portal appears and a young girl is seen. Reed Richard's reaches out to the girl and pulls her from the portal.
A bunch of demons then come racing through, and the girl is revealed as Mephisto, who has decided to use the Baxter Building as his base for conquering the world. Why? I dunno. Mephisto is a mystical guy, and surely the FF building has little to offer him, except resistance and trouble as he gets settled.
The FF fight Mephisto, pushing him back through the gateway. The Thing claps his hands together, and the resultant shockwave seals the portal tight.
What a load of bollocks.
One silly web.