An Enterprise away team investigates the crash of a Romulan vessel just inside Federation territory along the Neutral Zone. They discover an injured survivor (Steven Rankin) from the crash on the surface of the hellhole planet. A mishap causes Geordi to go missing on the mission, and the Enterprise is unable to locate him due to the violent electromagnetic storms. The heat is turned up under the entire situation when a Romulan Warbird commanded by Tomalak (Andreas Katsulas in what would become a semi-recurring role) ventures into the Neutral Zone and demands that Picard return the injured Romulan prisoner.
"The Enemy" is a perfect combination of multiple plot lines that come together to form a single coherent story. There are three interesting threads, which give the ensemble plenty to do, and all of which forward the overall plot. On the planet surface we've got Geordi stranded in a survival situation, which forces him to be innovative; there's a refreshingly dialog-free scene where Geordi must escape a pit by cleverly creating climbing spikes out of metallic ore fragments. Later, when Geordi is taken prisoner by Bochra (John Snyder), another Romulan crash survivor, their conversations provide a window into the Romulan mind. Ultimately, they must work together to survive and escape the planet surface — a TNG solution, to be sure. Their method of escape involves typical TNG tech made interesting by the uneasy symbiotic relationship that Geordi and Bochra find themselves in.
Meanwhile, Riker gets refreshingly riled up over the mission going bad, and he doesn't want to take crap from the Romulans. Worf finds himself in a position where he is the only possible donor who can save the injured Romulan's life. The dilemma shows how bitter hatred can persist for generations, and I especially like how the story doesn't go all sentimental and give Worf a last-second change of heart. His refusal adds an interesting wrinkle to an already delicate situation. Picard stops short of ordering Worf to cooperate, which is an intriguing choice. Picard lets the cards fall where they may, and the Romulan dies.
With the diplomatic situation quickly deteriorating (including some effective tough-talk by Picard), Tomalak enters Federation space. The showdown between Picard and Tomalak generates true suspense; "The Enemy" deals with the issue of cold-war-style brinkmanship better than any TNG story I can immediately recall. Picard's risky gesture of trust to defuse the situation is a memorable one. The final solution is perhaps a bit pat, but the story earns its peaceful payoff by bringing together all the plot threads with commendable precision.