(3x16) Light of the Foundation: Part 3, Episode 1
From somewhere far away across the Ehrban's galaxy-spanning network of wormholes, the Berol with whom they have again been at war for some time now launch a novel attack designed specifically to counter the technique the Ehrban used to end their first war with them, thousands of years ago: shutting down the wormhole network entirely. To make that effort futile, the Berol have launched a series of enormous, heavily armored carrier ships intended to penetrate as deep as possible into Ehrban territory and then, when the carriers are finally compromised or can penetrate no further, to release a swarm of smaller automated ships from inside themselves, some of which will proceed to establish shipbuilding facilities on any appropriately rocky bodies in the vicinity, so as to ramp up an attack on the Ehrban from all sides.
One such Berol ship has now penetrated the Asiron system, that on the other side of the portal from Sol, and then redirects to target the portal itself. It initially cruises through the Asiron system ignoring the Ehrban's forces without stopping, only slowly turning toward the portal. To make sure it never reaches Sol, Kron and the Horsemen cross through the portal to the Asiron system with all of the fleets under their command, to join the Ehrban forces in attacking it. Osan follows with them, and Metis follows him, against Aten's advisement. Thanks in no small part to their help, the outer carrier ship finally is breached mere moments before reaching the portal, but that only triggers the release of the warships within it. Because Metis is on the other side, Xio hesitates to immediately reseal the portal, instead her and the rest of the human forces in the Asiron system to retreat back to Sol immediately. They are unable to do so before a significant fraction of the Berol warships are able to pierce the portal and enter the Sol system themselves, with the retreating human forces only following behind them, and still more Berol flooding in behind them.
Many of the Berol ships focus on maintaining control of the portal to keep themselves from being shut out of either system, but the rest of those already through it scatter toward the inner planets. Xio leads the forces under his command inward in pursuit. The automated shipyards on Mercury are given orders to start producing automated warships programmed to eliminate the alien ships by any means necessary without disturbing any of the inhabited planets, as a backup measure and counter to the Berol's own shipbuilding plans. Meanwhile Kron and those loyal to him try to close in and regain control of the portal. Metis also continues fighting the war in the outer solar system, and is thought killed in the battle, but in fact is rescued adrift in space by Kron of all people, and recovers on his command ship thanks to the nanotechnology that makes them immortal.