Captain Archer is contacted by Admiral Forrest asking him to turn back to investigate a distress call from the cargo freighter ECS Fortunate. Archer finds that the freighter had been attacked by the Nausicaans, a race of space pirates. Archer provides supplies, manpower and medical assistance to First Officer Matthew Ryan, who is in command since the captain is injured. When T'Pol detects an alien form in the ship, the reaction of Ryan is violent and the Enterprise discovers that the officer is plot revenge against the Nausicaans, jeopardizing the space route for other freighters.
"Fortunate Son" is the weakest episode of this good series so far. The story of revenge of Officer Ryan is silly and pointless, since the guy is not totally wrong. The Nausicaans are pirates and attack the freighters, and the Starfleet does not take any action, therefore his attitude of despair seems to be very reasonable. The moral message of this episode in the end is blurred. My vote is six.
Title (Brazil): "Mercadores do Espaço" ("Merchants of Space")