2. book space opera Old Fleet
The swarm has been repelled so far, but they will not stop. They are not people. They have no inhibitions. They have no conscience. And they don't know mercy.
But in the heat of the battle, an unexpected hero was born. Captain Timothy Granger on the bridge of another time-tested warship will carry the battle to the enemy. He reveals his secrets. He finds their home world. They will destroy them before they destroy us. They'll save us all. Must. Otherwise we die.