In the first two seasons, Archangel was often assisted by Marella (Deborah Pratt). She had doctorates in Aeronautical Engineering, Electronic Engineering, Psychology, Microbiology, and French Literature, and was one year away from completing her Medical Doctorate as of the episode "Fallen Angel." Marella was last seen in the final episode of Season 2, "Short Walk to Freedom"; in Season 3, she was replaced by a series of minor characters. In 1987, at the beginning of Season 4, Archangel was suddenly (and unexpectedly) reassigned to the Middle East, and was not mentioned for the remainder of the series.