The Fantastic Four meet with the President of the United States to discuss a potential new threat involving the Cosmic Cube, a mysterious and reality-altering device being developed within the Baxter Building labs.

During the meeting, a powerful surge overwhelms Reed’s sensors, and the team discovers that a massive interdimensional event is unfolding at the Cube itself. Responding immediately, the FF return to headquarters only to come face-to-face with Thanos, who breaches the facility via cosmic projection.

This issue marks Thanos’s full arrival in the Ultimate Fantastic Four storyline as he reveals his knowledge of the Cosmic Cube and his interest in claiming it. As the arc begins, the team realizes the Cube may be far more dangerous — and far more desired — than they ever imagined.