“Harper/Delete” is episode five of season four of Andromeda.
The Andromeda Ascendant has been sent to recover something called File D from a Systems Commonwealth ship, the Magellan Melrow. When they get to the ship, it has been raided by Nietzscheans. The crew are not dead, but their mental facilities have been erased.
The damage wasn’t done by the Nietzscheans but by File D when the ship was attacked by Magog. The Nietzscheans merely scavenged it.
File D is a dangerous weapon, so the Andromeda goes to the homeworld of the relevant Nietzschean pride in order to recover it.
The pride is split in two – run by a brother and sister. The sister is the one actually running the pride, but the brother was the one who stole the weapon. So Dylan has to deal with both factions to get the weapon back.