This is the general discussion post for the episode 4.03 - Traitor. Spoilers for the whole series are allowed here
The Federation is expanding once again at an alarming rate, and with the annex of the most recent world Helotrix, Avon decides to go there to find out how the Federation is doing it. He sends Dayna and Tarrant down to spy, and they soon come across a resistance group led by a man named Hunda. It is soon discovered that the Federation is using a swift acting pacification drug, Pylene-50, and the operation is being led by a new security commissioner named Sleer. With Hunda's help, Tarrant and Dayna make contact with Leitz, a Federation officer who has been leaking information to the resistance. Leitz reveals where the drug is being made and a possible antidote, and Tarrant decides to put a stop to it despite Avon's orders not to get involved. However, Leitz is not a traitor after all, but acting under Sleer's orders to set up an ambush.