All the previous episodes led to this moment, the time when the Iconians returned and are bend on destroying the known races. It was them who where behind the Hobus explosion, the rise of the Vaudwaar, and so much more.
The story begins as we meet up with vanZyl, who has tracked down Sela. The fallen Empress is trying to reactivate a gateway, and has found that they lead to another Dyson Sphere, whose sun is blotted out by the massive fleet of the Iconians.
The alliance gathers in various efforts to undermine the Iconian powerbase, but to not much avail. But then it is discovered that the Krenin, specialists in temporal tinkering, weren`t destroyed by the Vaudwaar but went into hiding. This Delta Quadrant race is one of the few the Iconians more or less fear.
The decision is made to remake Annorax`s Temporal vessel, but the first temporal incursion results in the restoration of Romulus... only to find out that it has been completely taken by the Borg.