Growing up with a Klingon foster brother can be a unique experience, so it is no wonder that the human Nikolai Rozhenko has drifted apart from his Klingon brother, Worf, over the years.  Although Rozhenko entered Starfleet Academy in 2357, along with Worf, he grew dissatisfied and left the institution at the end of his first year.  Rozhenko had felt stifled by the rigid rules, finding science and the study of other cultures to be a far more rewarding experience.  In 2370, Rozhenko is stationed on the planet Boraal II as a cultural observer.  He soon gets deeply involved with the natives, and when atmospheric dissipation threatens all life on their world, Rozhenko takes matters into his own hands, saving the Boraalans... but breaking the Prime Directive in the process.

When it appears that he can do no more to save the Boraalan people, Rozhenko sends out a distress call to the Federation.  Starfleet dispatches the U.S.S. Enterprise-D -- on which Rozhenko's brother, Lieutenant Worf, serves as security chief -- to the planet to render aid.  When they arrive at Boraal II four days later, the Enterprise crew discovers that the deteriorating atmosphere will render the entire planet uninhabitable in 38 hours!  Sugically altered to resemble a Boraalan, Worf beams down to discuss the crisis with his brother.  What he finds is that Rozhenko has used a deflector shield to safequard a group of villagers, sheltering them in caves below the surface.

Later, aboard the Enterprise, Rozhenko appeals to Captain Jean-Luc Picard and his staff to help save the colony of Boraalans.  Picard refuses to further violate the Prime Directive, and will not even allow Rozhenko to return to the planet's surface to retrieve his log recorders.  However, Rozhenko bypasses the ship's security systems and transports the surviving vilagers to a holodeck which contains a facsimile of their caves.  Rozhenko enlists a grudging Picard into helping him find a new homeworld for the Boraalans, while using the holodeck to make the natives believe that they are merely walking toward other, safer lands.

A holodeck malfunction endangers Rozhenko's plan, but a combination of quick thinking by Worf -- who poses as a Boraalan "seer" -- and the rest of the Enterprise crew keep the Boraalans' pastoral culture relatively uncontaminated by the time a new home planet can be found for them.  When the Boraalans are transported to their new home on Vacca VI, Rozhenko stays behind with his Boraalan wife, Dobara, who is expecting their child.  His brother, Worf, departs, promising to tell their parents that Nikolai has finally found happiness.