In the midst of the evacuation, the gate activates and reinforcements arrive from Earth! Colonel Matthew Everett leads a team of commandos, telling Weir that General O’Neill sends his compliments. He relieves Weir of command, rescinds the evacuation order, and cancels the self-destruct. Earth has received their message (“Letters From Pegasus”), and they intend to fight to defend Atlantis.

Among the toys they have brought: rail guns intended for the Prometheus, but which they will install on Atlantis instead. The team will also lay stealth mines in space in the path of the Wraith ships, and will use a generator to power the city’s newly discovered chair room (“The Gift”). Preparations begin, as McKay tries to get the chair working, new pilots are trained on Puddle Jumpers, and Teyla trains the Athosians who have joined the fight.

McKay soon must report that there are only a few dozen Ancient drone weapons left in the system controlled by the chair — nowhere near enough to stop two Wraith hive ships. And when the Wraith easily detect and destroy the land mines, Everett is furious. But the assault on the city begins.

Wraith Darts begin making kamikazee runs on the city and the gunners open fire. Sheppard uses the few remaining drones to stop the first wave, and Teyla soon realizes that there are Wraith already in the city! The Dart pilots must have transported themselves to the ground before their ships crashed. The drone weapon is depleted, but perhaps the chair can at least be used to remote-pilot Puddle Jumpers on some kamikazee missions of their own.

Teams fan out to search for the Wraith, while Dr. Weir pursues the only lead they have on weapons powerful enough to stop the hive ships: the Genii’s nuclear bombs (“Underground”). They agree to speak with her, but when she arrives she is tied up and blindfolded. Prenim, a Genii leader, tells her that he is pleased her people are about to be destroyed by the enemy.