A couple of lurkers in Downbelow, Matthew Duffin (James Warrick) and Jaque Lee (Wylie Small) watch the Dyson come into port. At the same time, Lt. JG David Corwin (Joshua Cox) celebrates his promotion to Lieutenant. The senior staff discuss whether Ranger Marcus Cole (Jason Carter) should be invited, but Captain Sheridan (Bruce Boxleitner) and Ivanova (Claudia Christian) agree he must keep a low profile. Duffin and Lee watch an alien parasite merge into a man’s back. They don’t understand why the man dies.
Now that Corwin is a Lieutenant, Sheridan feels they have to sound him out carefully to see what he would think of their mission to oppose President Clark. Marcus Cole visits his friend Duncan (Aubrey Morris). Ranger One wants the Rangers to pull back from Earth space. Shadow vessels have been seen in Centauri space. Marcus looks for his fiend Samuel (Eric Steinberg), who tells him he can no longer work with him. Franklin finds something strange in a body he is examining. Samuel and his friend watch Duncan being taken over by the parasite.
Ivanova invites Corwin to a private meeting in her quarters to find out what he feels politically. He thinks there is another reason for the invitation. Marcus talks with Garibaldi (Jerry Doyle) about the strange behaviour of his friends. Then he goes to Doctor Franklin. Corwin shows up at Ivanova’s quarters with flowers, but when he realizes it is not a date, he says he found them outside her door. Marcus and the doctor are confronted with Samuel and Matthew holding weapons. The doctor surmises that parasites are taking over people.
Duncan tells Cole and Franklin that the parasites are Vindrizi and they are trying to save lives. Ivanova and Corwin talk about ends justifying means and respecting the chain of command. His answers show that he is loyal to Earth Alliance. Cole wonders what he has done to offend Ivanova. Their kidnappers want Franklin to cure one of their number who is sick. He tells them to take out the parasite.
Cole escapes from his captors and tries to call Security but the link will not work for him. But Ivanova detects this and Garibaldi dispatches a team to Brown 84. Cole rescues Franklin. The parasite hosts are volunteers, and the parasites are doing what they do to preserve the knowledge of their race. They prove it by willingly separating from their hosts. The lurker who died was a drug-user and that is what killed him. Franklin agrees to help. Ivanova reports to Sheridan that Corwin is unsuitable. Franklin talks about the Vindrizi with Garibaldi and Ivanova. He tries to get Ivanova and Cole back on good terms. She thinks it was Cole who sent the flowers and returns them to him; he thinks she is giving him flowers.
J. Michael Straczynski wrote the first half of the script, came down with a fever, and forgot how to finish it. Because of this, the second half of the story doesn’t quite jell with the first. There are other problems with story, notably some strangely inappropriate behavior. For example, Cole is being held against his will by people he thinks are harboring an evil parasitic alien, and all he can think of is why Ivanova doesn’t like him anymore. Corwin does show that perfectly good guys can disagree with you politically, which might be an important message to take with us.