The Game

"The Game" is the fifteenth episode of the third season of Stargate: Atlantis.

Synopsis
Major Evan Lorne reports back from M4D-058 and tells them they encountered a race of humans who has Dr. Rodney McKay's face on their flag. They learn that a game McKay and Lt. Colonel John Sheppard were playing is actually happening in reality. However, this also causes friction between McKay and Sheppard's worlds, who are on the brink of war.

Plot
For two years, Lt. Colonel John Sheppard and Dr. Rodney McKay have been playing a computer game left by the Ancients, in which they each develop countries on opposite sides of a river in competition with one another. While McKay has been pushing his country ("Geldar", named after a former romantic interest of McKay's) to develop technologically, Sheppard has been encouraging his ("Hallona", named by the Ancients who created it) to develop its military.

On a routine survey mission, however, Major Evan Lorne's team discovers that it is not, in fact, a game. Their countries, and all the people in them, are real; living on a planet somewhere in the Pegasus Galaxy. With a satellite network in orbit to track their development and Ancient technology to receive the "players'" instructions, their civilization has, in fact, been a Lantean social experiment. The team has stumbled upon McKay's country (easily identifiable by the multitude of paintings of his face throughout the village), they go to the planet to investigate.

The team visits Geldar first, where they are met by Nola; she immediately recognizes McKay as their "Oracle", and explains that their people were given life thousands of years ago and guided by the Oracle through a console, but then all communications suddenly ceased — interrupted by the war with the Wraith. Unknowingly, McKay and Sheppard have picked up where they left off.

While McKay stays with Nola, Sheppard takes Teyla Emmagan and Ronon Dex to visit "his" civilization, located across the river. There they meet Baden, the aggressive leader of Hallona. He reveals that at the command of Geldar's Oracle, the Geldarans have begun mining for valuable coal under his country. He believes that the proper response is to launch an attack.

The two leaders are brought back to Atlantis to learn about the Ancient technology and to have their dispute mediated by Dr. Elizabeth Weir, but they refuse to cooperate. Tensions are high, and as a result of Sheppard and McKay's "game", the two peoples now stand on the brink of war. Despite their best attempts, neither Weir, McKay, nor Sheppard can convince them to make peace, and things quickly escalate into an all-out attack.

On both sides, it soon seems as if the other side has achieved total victory. Geldar is seemingly overrun by the larger Hallonan army and its people slaughtered, while Hallona seems to have been devastated by Geldaran bombing runs (completed by use of dirigibles). After both sides admit defeat, McKay and Sheppard reveal to their respective countries that the whole display was a ruse in order to show them how costly a war could be. The Daedalus, having arrived earlier in expectation of the conflict, was transmitting fake data to each control console while using precision attacks to simulate the damage outside. It seems as though a peace has been achieved, and both civilizations set out on their own, no longer constrained by the game - which has now been deactivated and sealed at Weir's command.