Many years ago, the Federation made contact with a mysterious species called "The Children of Tamar". These beings look reasonably humanoid, but they are completely impossible to understand. The Universal Translator translates their language into English easily enough, but the words and phrases that come out appear to make no sense. As a result, no relations could be established with them. As this episode opens, Picard is briefing the crew on their new mission. A Tamarian vessel has travelled to the El Adrel system and began transmitting a homing signal towards Federation space - clearly they want to talk again. Picard orders a course set, confident that his people will be able to overcome the language barrier.
On reaching El Adrel, Picard opens communications with the Tamarian ship. A pair of aliens - apparently Captain and First Officer - make attempts to communicate by saying the following : "Rai and Jiri at Lungha. Rai of Lowani. Lowani under two moons. Jiri of Ubaya. Ubaya of crossed roads. At Lungha. Lungha, her sky grey". When Picard responds by offering to establish formal relations, the two aliens look at each other for a moment and the First Officer bursts out laughing.
The two then have what appears to be a brief argument, which culminates in the Captain declaring "Darmok and Jalad at Tanagra". Both he and Picard are then beamed off their respective bridges onto the planet below, where the alien Captain pulls a knife and brandishes it at Picard, again calling "Darmok". The episode then follows two strands - in one, Riker and the remaining crew attempt to both recover Picard and establish communications with the Tamarians, while in the second Picard must deal with the alien Captain.
Picard declines to fight the Captain, and the two settle down to try and make camp. Picard is unable to light a fire, but the Tamarian soon has a bonfire going. He performs a ceremony of some kind which involves touching his forehead, then settles down to sleep. As Picard shivers the Captain picks up a burning branch and throws it to him, declaring "Temba, his arms wide". Picard interprets this as "Here, take it".
Meanwhile, in orbit the Tamarians are sending a particle scattering field into the atmosphere to prevent communications or transporters from working. Riker sends a shuttle down to the surface, hoping that the Tamarians are not willing to risk a conflict by firing on it. However, the Tamarian ship uses a carefully controlled energy weapon to disable the shuttle just badly enough to force it to return to the ship. Geordi suggests that he may be able to boost the transporters sufficiently to break through the scattering field, but it will take considerable time. Riker okays the plan, and Geordi sets to work.
The next morning Picard wakes to find the Captain gone. He sneaks into his camp and takes a look at what looks like a diary or logbook of some kind. As he is doing this the Captain runs up, again waving a knife around. Picard declines to fight him - but when he hears a monstrous roar in the distance he realizes that the Captain is actually offering him protection from some kind of alien. The beast soon appears - it is apparently some form of semi-energy being which seems to fade in and out of sight. As it approaches, the Tamarian continues to try and talk to Picard. He soon realizes that that the Tamarian is describing actual people, places and events - his species communicate entirely by metaphor, citing examples from their history. At that moment the monster appears behind him, knocks Picard down and attacks the Captain.
Riker orders Geordi to make an attempt to beam Picard up, even though the engineer is far from sure that it will work. Geordi locks onto Picard - preventing him from helping the Tamarian as the beast lands blow after blow. The attempt fails anyway, and Picard rushes to the aliens side as the creature retreats of its own accord.
As Picard cares for the badly wounded Captain below, the Tamarians deepen their scattering field to make any further attempt to beam Picard off the planet totally impossible. Analysis of their ship shows that they cannot break through the shields and disable the particle emitter in one volley, but Geordi suggests that they might be able to knock out the generator pathways supplying the device if they modify the phasers. They can then beam beam Picard up and retreat before the Tamarians can react. Riker approves the plan.
On the planet, night has fallen. Picard questions the alien Captain about his language, getting the phrase "Darmok and Jalad at Tanagra" over and over. When the Tamarian declares "Tanagra on the ocean", he realizes it is an island. Darmok and Jalad are two people who arrived separately. They fought a monster on the island, and left together. Picard realizes that the Tamarian is trying to reproduce the event, hoping that they will have to overcome their differences to survive the beast on El Adrel. When the Captain asks Picard for a story in return, he tells it the legend of Gilgamesh and Enkidou. As Picard finishes his story, the Tamarian dies.
The next morning, the beast approaches again. In orbit, Riker orders Worf to fire on the Tamarian ship. They knock out the scattering field and beam Picard aboard - but the Tamarians fire back, disabling the warp drive and crippling the ship. As the Tamarians prepare to finish them off, Picard arrives on the bridge. He astounds his crew by holding a conversation with the alien First Officer in fluent Tamarian, explaining what has happened. He offers them their Captains effects; they accept the logbook, announcing "Picard and Dathon at El Adrel" - clearly a new metaphor has been added to their language. They refuse to accept the knife, however, and depart.
In the aftermath, Riker enters the ready room to make a report to Picard. He finds him reading up on our own legends in the hope that it might help in our quest to understand the Tamarians. After Riker leaves Picard looks out of the window, holding the knife. He repeats the gestures the Tamarian Captain had made on the planet as a final gesture of respect.
To me, this episode perfectly sums up the whole philosophy of Star Trek. We open with a mysterious alien race who kidnap Captain Picard apparently in order to force him to take part in some form of combat. We might expect to see a story similar to The Original Series' "Arena", where Kirk fought a Gorn starship Captain. And indeed, Riker's situation on the Enterprise parallels this type of story to a large extent. Both Riker and Picard open the episode in an atmosphere of trust and goodwill toward the Tamarians. When this is apparently betrayed by the kidnap of Picard, Riker begins by testing the aliens resolve. He sends out a shuttle to penetrate their scattering field, only to see the Tamarians disable it. He then tries to out-tech them with a boosted transporter beam, but again this does not work. Finally, out of options and patience, he opens fire on them in the hope of disabling the ship and rescuing Picard.
Meanwhile, on El Adrel a very different philosophy is being played out. After his abduction Picard meets the alien Captain in a situation demanding mistrust, but where Riker protects his position and gradually uses more drastic means to resolve the situation, Picard makes attempt after attempt to communicate with his opponent. While Riker sits behind shields and preps his phasers, Picard stands unarmed before the Tamarian Captain, declaring again and again "no, I will not fight you". The two strands of the episode thus display diametrically opposed approaches to the problem.
Through both runs the attempt to crack the Tamarian language. When I first watched Darmok, I was utterly convinced that Picard or Riker would eventually modify the phase induction coils on a universal translator or some such thing, whereupon all the Tamarians would start speaking perfect english. Instead, when the monster first approaches Picard realizes that the Tamarian is talking in metaphor. It was a wonderful moment, I just sat up and said out loud "but of course!". This is followed up by the scene in which Picard cracks the mystery of "Darmok and Jalad", and tells the Tamarian the legend of Gilgamesh. That scene is absolutely flawless - superbly written, and the acting by Patrick Stewart and Paul Winfield is outstanding. We realize that the Tamarians are not enemies at all, but are in fact risking everything for a desperate chance to communicate.
At the climax, Riker launches his attack on the Tamarians and although Picard is beamed up the aliens return fire, crippling the Enterprise - the final failure of the aggressive approach to the problem. As they face destruction, Picard strides onto the bridge and orders a channel opened. He then talks to the Tamarian First Officer fluently in his own language, using all the phrases he has so patiently reasoned out on the planet below to calm things down. The 'enemy' that Riker fought so hard to defeat becomes a friend within seconds, once communications have been established.
There are then two nice touches - first the First Officer announces "Picard and Dathon at El Adrel". This gives us the Tamarian Captains name, and lets us know that a new story has been added to the Tamarian language. Later, we see see Picard performing the Tamarian ritual in his quarters as he gazes out at the stars. Each side has shared just a little of the others culture and become wiser for it.
So, we have an episode which is brilliantly written, wonderfully acted and contains a message which is classic Star Trek. Quite probably the best episode not just of TNG, but of any Trek series.