Chapter 8:
The Ultimate Being is born. Aya fights it, but its mitochondria causes it to evolve at an alarming rate. Aya sets the vessel's boiler pressure dangerously high, so as to destroy it with the Ultimate Being on board.
...
In the end, the Tennysons attend the opera with Aya and Maeda, where Aya's mitochondrial powers allow her to resonate with the audience members, their eyes ominously glowing.
The End