The USS Enterprise-D is investigating unusual solar flares and magnetic activity in the Delos system. The crew are in awe of the visual display on the main viewer. Lt Commander Data reports an unusual amount of solar activity, as well as an irregular magnetic field. Wesley Crusher then reports huge numbers of X-rays hitting the main deflector. Suddenly his console starts flashing and overloading. When Lt Worf orders Engineering to increase power to forward deflectors to compensate to the increased activity, the Engineering consoles start to overload too.

Counsellor Troi tells Captain Picard that the level of tension on the ship is increasing, which Picard finds understandable under the circumstances. Suddenly, the Enterprise receive a distress signal from the Ornaran freighter Sanction orbiting the fourth planet of the system. The bridge crew, Picard and Commander Riker in particular, are perplexed by the apparent incompetence of the freighter’s crew.

Act One

The Enterprise reaches the freighter. The crew have a few minutes before the freighter is destroyed. Picard tries to discern the problem from the freighter’s captain, but T’Jon just says that he’s “lost something” and that he is unable to use the main thrusters. He also states that “the computer is not working very well”.

The Enterprise tries to use a tractor beam to pull the Sanction out of orbit, but that fails, as the electromagnetic radiation from the system’s sun makes a lock-on impossible. Data determines the Sanction’s problem by connecting to its computer : their electromagnetic coil is damaged. Picard offers to beam a new one over to them, but the captain admits he doesn’t know how to install it, despite being captain for a long time. He asks his crew if anyone can do it, but there is no one qualified on board.

Worf warns the rest of the bridge crew that the Sanction is entering the planet’s atmosphere, and will not last long. Instead of risking beaming their crew over, due to the solar interference, Yar attempts to beam them to the Enterprise by interconnecting both transporter system, though quickly gets irritated by the freighter crew’s attitude and inability to follow simple instructions. On the first attempt, the cargo of the freighter is beamed over instead.

Act Two

Riker and Yar momentarily stare at the cargo in disbelief, wondering why the crew would value it over their own lives. With little time to lose, Yar clears the cargo to cargo bay 11 and attempts to beam again. She is able to beam four onto the Enterprise in the nick of time. Two are left behind on the Sanction, however, and Yar does not have enough time to make another attempt before the freighter is incinerated re-entering the planet’s atmosphere.

When the crewmembers, two Ornarans, T’Jon and Romas, and two Brekkians, Sobi and Langor, arrive, they are very anxious to see the cargo. Even though two of those aboard the freighter have been lost, the primary concern of all four is the cargo. The Ornarans, named T’Jon and Romas, claim that they have paid for the cargo, therefore it belongs to them. The Brekkians, Sobi and Langor, argue that since the payment was lost on the destroyed freighter, the cargo still belongs to them. Sobi and T’Jon begin to fight, using their natural electric charges, until Yar breaks it up by shooting at them with a phaser set on stun.

Yar is worried by the ability of their visitors to shoot electrical charges from their hands. Riker wonders if the strong magnetic field in the system could be the origin of their power. Yar would like to know more, so she could prepare to defend the ship, just in case.

On the bridge, Data informs the captain that the only record contact with this system was over 2 centuries ago, when a scout ship reported 2 inhabited planets, one of which was on the verge of discovering space travel. Troi find is strange that none of the visitors have remorse about their comrades, while the barrel is a great source of anxiety.

Picard, Riker and Data leave for the observation lounge, where the four passengers were taken. T’Jon and Romas ask Picard if the Enterprise crew could repair the last two ships they have. Data thinks it’s possible, and Picard give the order to proceed. T’Jon reveals that the cargo is felicium, a medicine that their planet needs to combat a leathal plague. Langor and Sobi note that the medicine is very expensive to make, and they cannot give the medicine when payment has not been delivered. Both parties argue, none of them willing to change their position on the subject. Then, T’Jon reveals that Romas and himself are carrying the plague, and Captain Picard now realizes that the “plague” they have may infect the entire ship, as the solar flare may have caused a malfunction in the biofilters. He puts the ship on med alert.

Act Three

As the Ornarans suffer from their lack of medicine in sickbay, the Brekkians continue to refuse them the cargo. Doctor Crusher reveals that she cannot find a cause of the signs of infection. She is also not sure if the plague presents any danger to the crew of the Enterprise.The Ornarans entreat Picard to give them the felicium, stating that if he does give them the medicine, he will be a party to the murder of an entire civilization. Picard offers to talk to the Brekkians.

In their quarters, The Brekkians are enjoying their stay. Picard enters, to seek an agreement. He asks them to give enough for the Ornarans’ own immediate needs. The Brekkians agree to “two doses for immediate use.”

In the cargo bay, Langor removes the casing and measures out two doses. The Brekkians have focused on increasing the potency of the felicium, and a single barrel contains over 4 billion doses. There is no cure for the plague, and a dose is effective for about 72 hours before the symptoms return. But the felicium completely inhibits the disease. It is revealed that Brekkian society is entirely dependent on the trade of felicium with the Ornarans; they have no other industry, nor do they need it. The Ornarans provide all the goods they need in return.

Dr. Crusher goes to sickbay and observes T’Jon administer the drug to Romas and then himself, both instantly feeling better, free of any sickness and both exhibiting the same euphoric daze. Crusher furiously informs Picard that the “medicine” is really an addictive narcotic, and the “plague” which the Ornarans fear so much is just the symptoms of withdrawal they suffer if deprived of the drug for too long.

Act Four

Data and Riker research the history of the drug which confirms the contraction of the Ornaran plague, though there is not much detail. 200 years ago, the Onarans were technologically advanced, and the Brekkian were not. Then suddenly, Onara was stikken by a davastating plague. Somehow, a cure was found in a plant that could only be found on Brekka. A tradding situation developped between the two planets.

Dr. Crusher interjects, convinced that the plague has already been cured, but now the Ornarans have become dependent on the addictive nature of the medicine. To Crusher’s frustration, though, Picard says he cannot intervene in their societies, despite Crusher’s belief she can develop a non-addictive version of the drug. Then, the Enterprise-D receives a signal from Ornara. Someone named Margan wants to contact T’Jon, so Picard, Riker and Crusher go to the guest quarters.

Meanwhile, Wesley Crusher wonders aloud how – and why – people let themselves become addicted to drugs. Initially, the inquiry is directed at Data. However, Yar jumps in and answers for him: drugs have their draw for people in desperate circumstances. Alluding to her own possible use of drugs on Turkana IV, where she was born and grew up an orphan, Tasha explains that drugs often seem to solve problems…which is enough for the common addict, even though nothing has improved in the real sense. When Wesley fails to comprehend all of this, Tasha assures him it’s just as well.

In the guest quarters for T’Jon and Romas, Margan desperately pleads that the Ornarans on the Enterprise-D must get the felicium to Ornara. T’Jon attempts to explain the situation, but Margan stops him and stops transmission. T’Jon, frustrated, attacks Riker with an electric bolt and demands that the Enterprise-D send the felicium to the planet. Picard does not believe he will kill, and refuses to give him the felicium. T’Jon releases Riker.

Act Five

Langor comes to the Ornarans’ guest quarters and asks to talk to Picard. He and Crusher go to the Brekkians’ quarters where they offer to “give” the drug to the Ornarans. Picard realizes that they have been purposely exploiting the Ornarans, and that they need to give the medicine now to keep them desiring more of the drug. Crusher realises that the Brekans were also infected 200 years ago, but manage to break out of the addiction, taking care to not tell the Ornarans. Picard tells the Brekkans that he cannot tell the Ornarans without violating the Prime Directive, much to Crusher’s visible frustration.

In the cargo bay, the Ornarans prepare to leave with the coils they need for their ships. Picard arrives with the Brekkians. He informs them they can leave with the medicine, however, he refuses to repair the Ornarans’ freighters, again citing the Prime Directive of non-interference for both decisions. Without the ability to repair their ships, the Ornarans will therefore not be able to obtain the drug anymore and begin to painfully withdraw from it. Additionally, they will believe they are dying. After beaming Sobi, Langor, T’Jon and Romas down to Ornara with their cargo, Picard orders helmsman La Forge to put some distance from the Ornaran system and the Enterprise-D heads for the Opperline system, a place never before explored.