A friend of Talia comes to Babylon 5 to negotiate a deal to help Mars become more self-sufficient, when a man calling out "Free Mars!" electrocutes him.

A 100% fatal and 100% contagious plague is killing the Markabs. Dr. Franklin tries to find a cure, but is being opposed by the Markabs themselves, who believe the plague only affects the immoral.

An Earth Force investigator comes to Babylon 5 with Lt. Keffer's last recording, asking the ambassadors if they recognize the ship in it. Meanwhile, Londo takes steps to remove himself from the Shadows, and Sheridan takes the White Star out for its first mission.

Marcus starts snooping around Downbelow when some of his contacts start behaving unusually and a lurker is found dead with a strange creature bonded to his spine. Ivanova investigates Corwin's loyalties when he receives a promotion.

The new Vorlon ambassador arrives, Sheridan decides it's time to test just how effective telepaths are against the Shadow ships, and Franklin is on walkabout in Downbelow and falls in love with a singer.