short summary as far as can be from chatters:
Following the fourth novel a large scale battle ensues at the capital of the Abh Empire. The massive Hania Federation fleet invades and destroys everything. Lakfakalle falls along with a major character's death.

Lafiel survives and gets promoted along with a new ship.
On the other side of plane space Duhirr is engulfed in battles on enemy territory.
Apparently, this book closes the first part of the Seikai no Senki story line. And there will be more to come.
