While exploring the planet Riker, Data and Yar are attacked by an energy sphere. Lieutenant Yar destroys the sphere, but not before it traps Riker in a transparent cube. Then, after Picard and Dr. Crusher beam down to investigate the crisis, the ground swallows them into a subterranean cavern, seriously injuring Dr. Crusher.

Although Data is able to free Riker, the away team is unable to locate Picard and Crusher. Meanwhile, the U.S.S. Enterprise comes under serious attack by an invisible enemy, which La Forge desperately fights to contain. Until the ship can adequately defend itself from the attacker, La Forge cannot beam up the crew members on Minos.

Back on the planet, Data finally locates Picard and Crusher. The team discovers that the attacks are coming from a computer-generated weaponry system which has gone out of control and has destroyed the civilization that created it. Fortunately, the team is able to turn the system off in time to save the planet ... and themselves.

Onboard the U.S.S. Enterprise, La Forge is able to destroy the invisible enemy and beam Picard, Crusher, Riker, Data and Yar aboard.

"Encounter at Farpoint" - While Worf takes the saucer section to Farpoint Station, Picard takes the warp drive section to meet up with the Q entity.

"Arsenal of Freedom" - Geordi takes the Warp Drive section in order to destroy the defense device on Minos, while Chief Engineer Logan takes the saucer section to safety.

"Best of Both Worlds - Part II" - In order to retrieve Locutus/Picard, the Enterprise separates into two sections, with Riker in charge of the Warp Drive section, and Cmdr. Shelby in command of the saucer section. While the Borg attack the warp drive section, the rescue shuttle with Worf and Data launches from the saucer section.

Part of the reason that we don't see more saucer seperations is due to budget constraints.