Taken back through time, Picard and the others must find Data and stop the alien incursions into Earths past. The crew return to the 24th century and discover they have left Picard behind but have a visitor from the 19th Century who most definitely should not be there.
Reg Barclay is terrified of the transporter. When finally encouraged to use it, he discovers the horrors he always feared seem very real.
A peace envoy places a fatal grip on Deanna Troi. When challenged he refuses to release her - can the crew save her from a premature death?
The Enterprise discovers an old Federation craft lost 70 years before crashed on the surface of a Dysan sphere. The transporter appears to have a pattern locked inside it, and when they cause it to rematerialise Captain Montgomery Scott (Scotty) appears. Later on, Geordi and Scotty return to the crashed ship to try and recover data from its computer core, and are alarmed when the Enterprise disappears completely.
The Enterprise crew suffers bizarre consequences following a secret, unwelcome alien visit. A medical examination reveals that Riker's arm has been cut off and then re-attached without his knowledge.
``Q'' appears with a fatal interest in a young student who is visiting the Enterprise. Is she really a member of the Q continuum and, if so, can she be trusted with her powers?
A bizarre transporter mishap transform Picard, Ensign Ro, Keiko O'Brien and Guinan into children just as a band of renegade Ferengi attack and take control of the ship.
Worf, Alexander and Troi are trapped on the holodeck when an experiment linking Data to the main computer goes wrong. Suddenly all the Holodeck characters take on the appearance and characteristics of Data, the holodeck safeties are off, and there's no escape.
Data risks Picard and Geordi's lives in order to protect other ``living'' machines, the Exocomps, when Riker orders their destruction in order to save an experimental mining project that is going wrong.
After resigning his command to participate in a dangerous secret mission to investigate a metagenic weapon rumoured to be in development at a secret base deep in enemy territory, Captain Picard is taken hostage by the Cardassians.
While under the command of an unfeeling new captain, the Enterprise attempts to rescue Picard from the Cardassians. Meantime Picard is tortured by the Cardassians in the belief that he knows the Starfleet plans for defending a star system near the Federation border that they intend to invade.
Reanimated by Reg Barclay, a calculating Sherlock Holmesian character - Professor Moriarty from Elementary, Dear Data - traps Picard and others in a holodeck simulation.
During an investigation into the disappearance of the crew of a monitoring station, Geordi becomes enamored with a beautiful and mysterious Starfleet lieutenant accused of murder.
Forced to impersonate a Romulan Intelligence officer, Deanna Troi becomes a pivotal part of an elaborate defection scheme. In the meantime, the Enterprise plays host to a man who was once a starfleet ensign but defected to the Romulans but has returned claiming to carry a message from Ambassador Spock.
After Picard loses his life in a surprise attack, ``Q'' gives him the chance to change his destiny, and avoid the brawl in which he was stabbed through the heart. But will Picard be the same man he was if history is re-written?
On a visit to Deep Space Nine, Worf is accosted on the promenade by a trader who claims his father, Mogh, is still alive. Worf is angry at the prospect that his father might be alive and thus bring dishonour upon his whole family, and goes with the trader.
Meanwhile, a freak acident causes Data to embark on a journey of self-discovery after an alien probe gives him a vision of his father, Dr Noonian Soon.
Imprisoned in a society of peaceful Klingons and Romulans, Worf risks his life to show the younger Klingons their lost heritage and inspire them to claim their honor.
The Enterprise is evacuated while it is purged of accumulated radiation. Returning to collect his saddle from his quarters, Picard discovers that the engineering crew who are running the decontamination operation are not all they seem.
Picard falls in love with the new head of Astro-physics and must face up to the reality of the conflict between his emotions and making unbiased command decisions.
When Picard's old archeology Professor comes on board and invites him to join the search for a great mystery, Picard is severely tempted but says no. When the Professor's shuttle is attacked soon after leaving the Enterprise, Picard finds himself in a race with Cardassians, Klingons, and Romulans to solve a four-billion-year old genetic puzzle. But will solving it unleash the galaxy's most dangerous secret?
Riker is playing a leading role in a play about a patient in a mental hospital, when he finds that reality and fantasy have become intermingled. Apparently trapped in an alien mental hospital, with little memory of the past, Riker becomes convinced he is going insane.
After his experimental craft fails and the pilot is killed, a pioneering Ferengi scientist is found dead, and Beverly Crusher risks her career to prove he was murdered. Soon she becomes so enravelled in the mystery that she disobeys a direct order from Picard and sparks off a major diplomatic incident. Desperate, she decides to try the fatal experimental for herself.
Worf finds his faith sorely tested when it appears that the greatest Klingon warrior of all time (K'ahless) has returned from the dead to reclaim the empire.
Returning to the site of an eight-year-old mission, Riker encounters an identical double of himself created by a transporter failure, who tries to rekindle his relationship with Troi.
Personalities clash when the two Rikers (our Commander Riker, and his duplicate Lt Riker) must go on a mission together to extract data from the computer core of the deserted research station.
At the end, Lt Riker takes on the name Thomas Riker and goes off to make his own career in Starfleet. He turns up again in the DS9 episode The Defiant.
The Enterprise is frozen in time on the brink of total annihilation, and Picard must figure out how to rescue it without destroying it.