The Baxter Building is rocked by an earthquake, and while the others investigate, Sue finds a story in the newspaper regarding her father breaking out of prison. When Reed and the others look for Sue to investigate how an earthquake caused an entire city block to sink into the ground, they find her missing but she left a note saying she's going to police headquarters.

These earthquakes are caused by the Mole Man who is using a device to cause city blocks in New York to sink into his subterranean realm. When the next city block sunken to his level brings Sue into his clutches, the Mole Man has her captured. When the other FF members travel down to investigate the cities, they come into conflict with the Mole Man and retreat back when Mole Man threatens Sue's life.

When the Avengers try to get involved, the FF tells them to stand back and let them handle it. Going after the Mole Man, the battle of his Moloids, restore the sunken city blocks, free Sue, and destroy the Mole Man's machine. However, during the battle Sue is injured and rushed to a hospital. There Sue and Johnny's father Franklin arrives, and when the police attempt to take him into custody, Reed appeals for them to hold off on arresting him until Franklin can see his daughter conscious one more time.

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