The Sinister Secret of the Sentry!

Johnny, Crystal and Ben are out grocery shopping for the team when suddenly they are advised by the store owner that the Fanasti-Flare has been fired into the sky. Rushing back to their Baxter Building headquarters where Mister Fantastic has been tracking the location of the Mad Thinker, whom he believes has been responsible for two previous attacks on the group. Having pinpointed his location by keying into the Puppet Master's radioactive clay, the Fantastic Four rush to that location.

Meanwhile, in Caste Doom in upstate New York, Doctor Doom's technicians begin working over the various devices that were stolen from the Baxter Building. After putting some of his technicians in line, Doom then checks on his latest acquisition: A Kree Sentry. He learns from one of his technos that the alien technology is proving hard to crack, but Doom refuses to surrender to anything, even advanced alien technology. Meanwhile, the Fantastic Four arrive at the Mad Thinker's hideout to find that it is in ruins, and a dead-end in their search to uncover the identity of their mystery attacker.

Elsewhere, Doctor Doom has unleashed the Sentry robot on the kingdom of Atlantis, leading the Sub-Mariner to believe that it is an attack from the surface world. When Namor attempts to engage this robotic attacker, it lures him to the surface where their battle is witnessed by a cruise ship. When reports get out, Crystal contacts the rest of the Fantastic Four about Namor's battle and they fly to the site. As they arrive, Namor has been buried under tons of rock and they engage the Sentry. As they battle the robot, Namor breaks free and resumes his attack, striking the robot so hard he causes the circuits to fuse, ending its threat, but also makes it impossible for Reed to learn the identity of their attacker.

Just then a number of Atlantean soldiers emerge from the waters to inform their ruler some bad news: While he was distracted in battle, someone broke into the kingdom and stole the Horn of Proteus.

Recurring Characters

Fantastic Four (Mister Fantastic, Invisible Girl, Human Torch, Thing, Crystal), Sub-Mariner, Lord Vashti, Senty #9168, Doctor Doom

Continuity Notes

• Chronologically, Sentry #9168 was seemingly destroyed when it attempted to thwart a manned mission to the moon in Fantastic Four #98.

• The Horn of Proteus was last seen in Sub-Mariner #21 when it was used during an attack on New York City by Namor and his army.