Scorched Earth (S04E09)

Thanks to SG-1, a civilization known as the Enkarans have been transplanted from a Goa'uld slave planet to a safer, more hospitable world. Soon after the Enkarans settle in, however, problems arise. One of their villages is attacked by a mysterious ship that appears to pose a threat even more formidable than that of the Goa'uld. SG-1 investigates and discovers that the mystery ship has no hostile intent — it is merely terraforming the planet in order to make it habitable for the Gadmeer, a long-dormant alien species. Lotan, a biomechanical liaison created by the Gadmeer ship, explains that once the terraforming procedure has begun, it cannot be halted. To do so would mean extinction for the Gadmeer. On the other hand, a completion of the terraforming process will mean certain death for the Enkarans. SG-1 must find a solution to this ethical dilemma, or face the extinction of an entire species. (Metro-Goldwyn-Mayer (MGM))