Thanos’ plans enter their final phase as the Cosmic Cube reaches a critical level of evolution. The Cube begins manifesting massive bursts of energy, fracturing space and warping the environment inside the Baxter Building. Reed struggles to stabilize the Cube, realizing it is developing sentience — and that Thanos is influencing it from across dimensions.

Sue attempts to break Reed from his obsession, warning that the Cube may soon become uncontrollable. Johnny and Ben prepare for direct confrontation as Thanos begins forcing his way into physical reality, using the Cube as a bridge.

As the issue reaches its climax, the FF face their greatest threat yet: the Cube forms a colossal energy construct, opening a gateway large enough for Thanos to finally emerge. Reed is forced to decide whether to protect the Cube… or destroy it to save Earth.