While surveying land on a Federation colony known as Melona Four, Riker, Data and Dr. Crusher are suddenly interrupted by the appearance of a massive, crystal-like structure which begins to descend toward the planet. Riker recognizes the object as the Crystalline Entity, and immediately begins herding the colonists together to search for shelter. The group watches in horror as the entity destroys the countryside with brilliant beams of light. All but two survive to find shelter inside a small cave - but the cave has a limited air supply. Riker tries to contact the U.S.S. Enterprise, but ultimately fails. Meanwhile, on board the Enterprise, the rest of the crew grow increasingly concerned over the violent disturbances detected near Melona Four.
