From the Back Cover
While serving on the U.S.S. Victory,
Geordi (LeVar Burton) and his friend Susanna (Maryann Plunkett) were part of an Away Team sent to investigate the disappearance of the colonists on Tarchannen III. Now, members of the same Away Team have begun to vanish as well!
When a stolen shuttle is spotted on course to Tarchannen III, the Enterprise pursues the craft to that location, but finds no signs of life. However, the planet's surface is apparently making Susanna ill. Lab tests show that her blood chemistry has been altered and she is slowly being transformed into an alien. What happened to the other Away Team members is happening to her...and Geordi is next. With time running out, Dr. Crusher (Gates McFadden) must find a cure before the transformation is complete and Geordi's identity is lost forever.