Dr. Pulaski join the crew in the episode while Dr. Crusher takes an assignment at Starfleet medical headquarters. The Enterprise flies to Odet IX to pick up several deadly "plasma plague" samples needed to develop an innoculate for an outbreak of plasma plague in the Ricellas system. Newly promoted Chief Enigneer Geordi La Forge replicates a series of containment modules to hold the samples at "zero growth" for the trip. At the same time a small energy ball slips through the hull of the ship and finds a sleeping Troi. The ball imprenates her. Thirty-six hours later she gives birth to a son which she names Ian Andrew, after her father.

While mapping a little know quadrant, the Enterprise encounters an "area of darkness." When they move closer to investigate they are swollowed up by the void. The sensors show nothing, communiocations are out, and they can't escape. Suddenly the view screen changes, showing a pair of eyes and a mouth. The entity identifies itself as Nagilum. He spins Dr. Pulaski around because she is a different construction, female. He asks if the crew has a limited existence, then kills an ensign to find the answer. He informs them he must kill one third of the crew to understand death.

The Enterprise is scheduled to meet with the USS Victory, but have three days to wait for them at the rendezvous, so the crew takes some time to relax. Geordi suggests that he and Data enjoy a Sherlock Holmes mystery on the holodeck. Geordi gets upset and exits after Data immediately solves the mystery. They get Dr. Pulaski to join them and Geordi instructs the computer tocreate an adversary capable of defeating Data. The computer creates a superintelligent Dr. Moriarty and gives the character access to the main computer. The character seizes control of the holodeck and continues to grow mentally, the transfers helm control to the holodeck and demands to leave the holodeck.

Responding to a ship in distress, the Enterprise finds an empty cargo freighter with a malfunctioning guidance system, captained by a man named Okana. The crew offers to fix his ship and beam him aboard while they do the repairs. As Okana fraternizes with several of the female crew members, two more vessels approach carring leaders from a neighboring system. One accuses him of fathering his daughter's child, the other accuses him of stealing one of the crown jewels of the kingdom. Both want the Enterprise to hand Okana over to them.

The Enterprise responds to a distress call from a planet inhabited only by Dr. Ira Graves and his assistant, Kareem Brianon. Dr. Graves has been working on bridging the gap between biological and machine intelligence. At the same time the Enterprise recieves another distress signal from a transport ship. They drop Data, Troi, Worf, and doctor Selar at Grave's wrld, then leave to help the transport. Dr. Selar learns that Dr. Graves is dying. While waiting for the Enterprise to return Data and Graves become close. Just as the Enterprise returns, Data walks out of Grave's office announcing he has died. The away team beams up with Kareem and Grave's body, soon after Data begins acting strangely, even dislaying emotions.

The Enterprise transports one of the Federation's best peacekeepers, a man named Riva. The warring factors of Solari V have petitioned the Federation for a negotiator. Due to Riva being deaf he travles with three interpreters which he calls his chorus. They sense his thoughts, expressions and feelings and each one speaks for a different part of his emotions. When Riva's chorus is killed by one of the factors after beaming down to the negotiations, Riva becomes distraught and feels he is unable to complete his task. Troi asks Picard for permission to beam down and try to negotiate with the factions, but before doing so she goes to Riva for advice.

After finding the USS Lantree totally lifeless, it's crew dead from the rapid onset of old age. The Enterprise sets course for the Lantree's last stop, The Darwin Genetic Research Station. When the Enterprise arrives they find the researchers experiencing the same swift aging as the crew of the Lantree. The researchers plead for Picard to evacuate their "children" for fear they will become infected as well. Picard refuses at first then allows Dr. Pulaksi to beam one child aboard in suspended animation. Pulaski feels that the child is safe, but icard is still not convinced. Pulaski takes the boy and Data aboard a shuttle to prove she is right and releases the boy from suspended animation. Eighteen minutes after examining the boy Pulaski experiences the first symptom of the diseaase.

Riker and Wesley greet a new group of crew members from Starbase 179 for the officer-exchange program the Enterprise is a part of. One of the crew members is a Benzite named Mendon. Picard asks Riker to serve aboard a Klingon vessel as first officer for the program. Riker prepares himself for the task by eating Klingon foods and brushing up on the Klingon language. Just before he beams over to the Klingon ship Worf gives him an emergency transponder in case of trouble. Mendon notices a strange organism on the hull of the Klingon vessel but fails to report it directly. Sometime after the Klingon ship has left he discovers the same organism on the hull of the Enterprise. This time he reports it immediately and is rebuffed by Picard for not reporting it sooner, but is then given the task to find a way to remove it. The Enterprise changes course to pursue the Klingon vessel. Riker earns the respect of the Klingon crew after he beat up the second in command. The Klingon captain questions Rikers loyalty after he discovers the organism on their hull. He cloaks the ship and changes course to intercept the Enterprise with the intent to destroy her.

In this episode the Enterprise makes it's way to Starbase 173 for crew rotation. Once they are there Picard is informed by an admiral that Commander Bruce Maddox is going to work on Data because he is close to being able to reproduce Data. He wants to take Data apart and study his positronic brain. Data expresses his doubts about the procedure to Picard and he refuses Maddox's request. Maddox gives Picard orders transferring Data to his command. When Data finds he cannot fight the transfer he decides to resign. Maddox goes to the Judge for the Starbase and claims Data is only a machine and can't resign. Picard challeges the Judges ruling nd forces her to hold a hearing. Data requests Picard defend him at the hearing and since the JAG office is new they have no staff, so Riker must argue for Maddox's position. Riker makes such a strong argument that Picard requests a recess.

The Enterprise is ordered to transport Salia and Anya to the planet Daled IV. For sixteen years Anya prepared Salia her role as leader to a war-torn race. Salia catches Wesley's eye and the two become close. Worf gives Anya a tour of the ship and when he takes her to sick bay she orders Pulaski to kill a patient because that patient has an infectious disease. Pulaski refuses and Anya transforms into a large beast. She ceases her attck when Picard arrives with a team from security. She is escorted back to her quarters only to find Salia gone. Anya and Picard find her speaking with Wesley and she immediately drags Salia back to their quarters. Picard asks Wesley to stay away from Salia because of the danger Anya poses to the ship. Salia sneaks out to Wesley's quarters after Anya falls asleep and just as the two kiss Anya appears. She turns into the beast again, then Salia changes into a beast also and challenges her.

When the USS Yamato self-destructs in the Neutral Zone duen tom masive system failures, Picard assumes the mission of it's captain. Captain Donald Varley believed he had found the home planet of the Iconians, a fabled race of incredible technology. On the way to Iconia, the Enterprise begins having system problems similar to the Yamato's. Picard beams down to the planet with Worf and Data to try and find a solution to their problem. The Iconian computer station probes Data with the same computer program that is damaging the Enterprise after it scanned the Yamato's logs. Picard sends Worf and the disabled Data back to the ship, hoping La Forge can help Data and save the ship.

The Enterprise makes orbit around Theta VIII after getting a report from a Klingon ship of spacehip debris in orbit around the planet. They beam a chunk of it aboard and find NASA markings along with an American flag having fifty-two stars on it dating it to the twenty-first century Earth. Detecting an area of breathable air, Riker, Worf, and Data beam down to the planet. They find a Casino-Hotel called "The Royale" made to resemble twentieth-century Earth. The investigate the hotel and find the remains of a Colonel Steven Richie who has been dead for 283 years. The crew also discover they can not leave the hotel. They read a sketchy diary from the dead Colonel and find an alien presence accidently killed all the other austronauts of his crew. Saddend the aliens tried to find some way to provide for the Colonel. They found a book called Hotel Royale among the crew's belongings and thought it was the way humans lived so they created the place for him to live out his remaining days. Unfortunately Riker, Data, and Worf are now stranded in the live novel.

The Enterprise finds a shuttle craft drifting in space and bring it aboard. Inside they find an unconscious Picard. Pulaski takes him to sick bay while the other Picard orders the logs from the shuttle craft downloaded into the ships computers. Data and Geordi access the logs and discover the shuttle is from six hours into the future and in six hours the Enterprise will be destroyed by an energy vortex. Several hours later the vortex opens under the ship and the captain tries to fly it away from the vortex. An energy bolt hits him and sends him across the bridge. Troi says the consciousness of the vortex is centered on Picard.

Worf has reached the tenth anniversary of his age of ascension and since there are no other Klingons on board to participate in the ceremony with him, Wesley gets a few of the crew together and holds the ceremony on the holodeck. Riker gets offered the command of the Aries and his father beams aboard to brief him. It is evident from the start that father and son do not have the best of relationships. Kyle Riker left his son to fend for himself fifteen years prior and Will Riker still holds it against him.

While Data conducts experiments to determine what is causing the planets in the Selcundi Drema System to have violent earthquakes and volcanic eruptions, he tunes the sensor array to scan wavelengths normally ignored. He comes across a low intensity radio frequency and hears the voice of a little girl named Sarjenka asking the question, "Is anybody out there?" He answers her with a simple "Yes." When Data discovers her planet is beginning to experience the same volcanic actifvity he goes to Picard and explains he has been in contact for some time with the girl. Picard orders him to break contact with her immediately and calls a private meeting with the senior staff in his quarters.

Q pays the Enterprise a visit after he is kicked out of the Continuum and bored from wandering around he galaxy. He informs Picard he wants to become a member of the crew. Picard considers is request then turns him down, so Q decides to show them what is out there. He transports them seven thousand light years with a snap of his fingers. Guinan warns Picard to start for home immediately because she was familiar with where they were. Picard decides to survey some planets while they are there and find the first plane they scan to be striped of all the machine elements from it's surface. A cube-shaped ship appears out of no where. The crew soon learn they are called the Borg, a humanoid race who have combined themselves with artificial intelligence and function with one collective mind. They send a scout to determine the strenth and weaknessess of the Enterprise.

Picard and Wesley leave for Starbase 515 in a shuttlecraft and shortly after the Enterprise receives a distress call from a Pakled ship. The Pakled's are a mentally limited race of scavengers. They claim their ship is broken and La forge beams over to help them fix it. After he finishes the repairs on their ship they take his phaser and stun him. They demand Riker to give them all computer records to make them smart or they will kill Geordi. Meanwhile, Picard goes into surgery at the Starbase because the replacement heart he was given when his own was injured in a fight with a Norsican when he was a cadet became faulty. They run into difficulties during the operation and the Starbase sends out urgent message for Dr. Pulaski to come assist. The crew race to save Geordi from the Pakled's or risk having to leave him there to go save their captain.

The Enterprise receives a distress call from the Ficus Sector while docked at Starbase 73. They discover that a ship called the SS Mariposa traveled there in the early twenty-second century carrying colonists, primitive tools, and technologically advanced computers. They find a group of 223 colonists and farm animals calling themselves the Bringloidi. After beaming the whole colony and their animals to one of the cargo bay, Picard learns that there was another group of colonists aboard the Mariposa. They find a colony of clones in a nearby solar system. Unfortunately the clones will no longer be viable in two or three generations due "replicative failure" in the DNA and they will all die. Picard suggests a solution by joining clone and Bringloidi societies together. The clones need new breeding stock and the Bringloidi need a new home. The clones refuse at first and attempt to steal fresh DNA from Pulaski and Riker. However when they are caught and the new clones are destroyed, they agree.

On it's way to Antedi III to pick up two delegates and transport them to Pacifica for a conference the Enterprise is intercepted by a transport carrying Lwaxana Troi. She is the representitive for Betazed at the conference. The crew soon learn her other purpose for being aboard. She is going through "The Phase." It is the time in the Betazoid womans life when she becomes fully sexual. Being widowed for several years she decides to find a new husband and she sets her sights on Picard. Riker and Data find Picard in the holodeck playing the role of his favorite character, Dixon Hill and hiding from Lwaxana. She eventually finds them and becomes interested in one of the characters of the holo-program, unaware that he is a mere hologram.

The Enterprise intercepts a class 8 probe carrying an emissary with information on their mission. Riker and chief O'Brien open the probe and find K`Ehleyr, a half Klingon and half Human woman. She informs them that a Klingon ship carrying a crew in suspended animation for seventy-five years is returning from a secret mission and are unaware the war between the Klingon Empire and the Federation is over. When they awaken they will begin attacking Federation outposts and colonies in the area. Picard orders Worf and K`Ehleyr to work together to find a solution to the situation after she suggests the only thing to do is destroy the Klingon ship when they find it. He is unaware that the two knew each other very well six years ago, but parted badly and the animosity is still present.

A Zakdorn named Sirna Kolrami beams aboard when the crew engage in war games between the Enterprise and an eighty year old ship named the Hathaway. His race is legendary for their strategic and tactical skills and he was sent to oversee the simulations. Riker and forty crew members command the Hathaway during the simulation. When the simulations begin Worf makes the Enterprise think a Romulan vessel is attacking by displaying a false image appear on their sensors and viewscreen. Picard falls for the trick and allows Riker to score several hits when he turns the Enterprise away from them. He changes the codes so Worf can not pull the same trick again. When the Enterprise is about to finish the Hathaway off the sensors pick up a Ferengi ship. Thinking Worf is trying to trick them again Picard ignores the ship. Only this time a real Ferengi ship is attacking them.

Riker is stabbed in the leg by the thorn of a plant while preforming a geological survey on an unexplored planet. The plant infected him with some microbes that if go untreated will reach his brain and kill him. Dr. Pulaski brings in a machine to stimulate the brain directly and keep him alive after the microbes reach his spinal cord. While Pulaski tunes the machine, it causes Riker to reexperience his life aboard the Enterprise. She soon learns that the memories he is having is affecting the metabolism of the microbes. With the help of Deanna, Pulaski finds the right type of memories, bad and stressful ones, then begins to dive the mircrobes from his body by stimulating his brain to increase the intensity of those types of memories.