A Call to Darkness — Michael Jan Friedman

The Enterprise discovers a lifeless, Federation research vessel, orbiting a plant hidden behind a mysterious energy shield. Over the strong objections of his senior officers, Captain Picard and an away team beam over in search of the missing crew -- And vanish.

But soon his captain's disappearance is not the only problem facing Commander Riker. For a mysterious disease has begun, ravaging the Enterprise crew. Now Riker must unravel the secrets of the planet below in order to rescue Picard--and prevent the
starship's destruction...