Synopsis
This issue's future 'previously' is from Avengers #38 where Sunspot tells his Avengers how Shang-Chi gained the power of replication from the Origin Bomb site in Japan. The past section is from #18 where the Cabal destroy another Earth and Proxima Midnight kills an alternate Sue Richards in Namor's arms.
Now in between we learn more details of Shang-Chi's upgrade. He volunteered to enter the quarantined city of Kobe because his senses told him there was an old energy there. That power took him through an initiation based on things in his own mind. An old sensei led him to a dojo where he faced a copy of himself in martial arts combat. They are equally matched until he accepts the duality within himself. Shang has to then ask for power from a dragon. The illusion fades and the Builder tech grants him its specific power - replication.
Meanwhile in the Wakandan Necropolis Sub-Mariner is having bad dreams about all the people he (and the Cabal) have killed on other Earths. Black Swan sees that the once-hero doesn't have the stomach for it, unlike his Cabal comrades. He went down this path for the sake of his Earth and his people, but now doubts his decision. Angry Namor tries to strangle her, but she is saved by the announcement of another incursion.
Sunspot and his newly-acquired AIM scientists come to the Savage Land where Thor and the Zebra Kids await them, as he begins his plan to save the world.