- Look, you show up here with your guns and your brush cuts, but when it comes to actually saving the city, you turn to the scientists. And every time, what you ask is impossible.— McKay
It looks hopeless. Weir arms the self destruct sequence and sets a 10 hour countdown. McKay begins dialling the alpha site so they can evacuate but is stopped by someone dialing in. An IDC is received through the gate — it's Stargate Command! A team of marines march cautiously through the gate, lowering their weapons as Sheppard and Weir come down to greet them. Colonel Everett introduces himself as the new military commander, he has arrived with supplies, men and weapons. McKay realises that Earth must have received the message they attempted to send and Everett confirms this. He also tells everyone about the ZPM that SG-1 recovered which is being transported aboard Earth's new battlecruiser, the Daedalus, which should arrive in a little under 4 days. The plan is to hold Atlantis until the ZPM arrives and the city's defences can be activated.
- Somebody please wanna turn off that self destruct?
A staff meeting is called where the details of the defence plan are discussed, the team from Earth have brought along a compliment of railguns, originally intended for Prometheus. These will help hold off any darts that attack while 6 nukes wired with proximity triggers will serve as 'space mines' to cripple the main Wraith ships. There is also a Mark II naquadah generator, although nowhere near as powerful as a ZPM, it should provide enough power to temporarily activate the city's chair platform and fire drones at any incoming enemies.
While Sheppard trains the newly arrived pilots in Puddle Jumper 101 and helps to deploy the space mines, Beckett is made to sit in the chair as McKay and Zelenka attempt to integrate the Mark II generator. They are successful, but McKay is concerned to discover that only a few dozen drones remain. The rest having apparently been used up in the first siege of Atlantis. His concerns are interrupted by a large number of blips appearing on the city's radar, but the objects appear to be rocks, heading toward them at high speed. It seems the space mines weren't as invisible as first thought and the Wraith have thrown dozens of asteroids from the outer edge of the system at them. With no way to disarm them, everyone looks on as the mines detonate harmlessly when the rocks get too close to them.
- McKay: Your mines make one hell of a bang Colonel, I'm sure the Wraith's ears are ringing.
Colonel Everett asks Sheppard for information on how the Ancients lost the first siege. In the hologram room, Sheppard goes through the basics of Pegasus Galaxy history. (In short, the Wraith won purely due to their vastly superior numbers. For every ship the Ancients destroyed, there were 7 more just arriving.) Everett informs Sheppard that he was a personal friend of Colonel Sumner, the commander that Sheppard was forced to mercy kill back in the Pilot episode. Everett is angry that Sheppard not only made it all the way into the Wraith facility only to not save Sumner, but that Sheppard himself was the one who fired the shot that killed him. Sheppard tries to explain that it was the most humane thing to do to someone who was being life-sucked by the Wraith but once again the city's radar interrupts them. This time it's a wave of darts incoming.
The railguns, combined with a flight of Jumpers and some well placed drones manage to fight off the first wave, but it's obvious that they'll never withstand a sustained attack. Sheppard has an idea though: the Wraith can't detect cloaked jumpers, so he plans to send one straight into a Hive ship's hangar bay. A jumper alone won't be able to do much damage, but Sheppard also has an idea where to get some more nukes, the Genii. McKay and Zelenka realise that it may be possible to link the chair platform to the jumpers so that Sheppard can fly them remotely. Teyla comes running into the room, she can sense several Wraith in the city, apparently dropped out of the darts that crashed in the attack. As search teams are dispatched to comb the city, Weir heads off to the Genii homeworld to negotiate for two nukes.
Beckett is back in the chair, with some effort he is able to tap into the jumper's systems remotely and power it up. Which is good because Weir is back with the nukes, the Genii agreeing to her requests in return for some supplies and the chance to see their new bombs tested in the field. McKay examines the bombs and realises that they are incomplete, they will work but it'll take roughly a day to finish them. He and Zelenka get to work.
The bombs are finished just in time and Sheppard sits in the chair, preparing to send the two cloaked jumpers after the hive ships, when the Mk2 fizzles out. It seems to have exhausted its power output and the chair is no longer functional. Another wave of darts is detected, much larger that the first. Without looking back, Sheppard says goodbye to Rodney and heads for the jumper bay.
Elsewhere in the city, Everett has been cut off from his team and is fighting with a Wraith. Despite unloading his sidearm into the the Wraith at point blank range it begins to feed on him. The process is stopped with a little help, but Everett is badly hurt.
Sheppard runs into Weir outside the jumper bay, she attempts to stop him but he persuades her that there is no other way, she lets him pass.
Ford and his team are ambushed by a squad of Wraith. After a brief firefight, only Ford and one of the Wraith soldiers is left. Fighting hand to hand, the Wraith begins to feed on Ford but another airman manages to pull the pin on a grenade and roll it towards them. The Wraith takes the brunt of the explosion, but they are both hurled over a balcony and into the sea.
In the control room McKay and Weir re-activate the self destruct as they watch John on the scanner, piloting his jumper towards the nearest hive ship.
To Be Continued
- Action Bomb
- Ambadassador: Wier travels to the Genii homeworld to bargain for some of their nukes to use against the hive ships. When they try to take her hostage in exchange for more C4 and supplies from Atlantis, she basically yells at them to stop wasting her time and accept the deal as offered.
- Asteroid Thicket
- Continuity Nod: The SGC responds to Atlantis's distress call from "Letters From Pegasus" with a full-scale military expedition and a plan to save the city.
- The Daedalus was first mentioned in the SG-1 episode ''Moebius'', where it was being readied for a voyage to Pegasus. The ZPM it's transporting is the same one SG-1 discovered during their time-travel shenanigans in ancient Egypt.
- Darkest Hour: Happens twice in the episode. The first time is just before The Cavalry arrives as the city is almost evacuated and Weir and Sheppard arm the city's self destruct sequence. The second is the episode's cliffhanger where Sheppard decides to suicide nuke a Hiveship, Teyla might be dead, Ford and Everett are cornered by Wraith soldiers and the Wraith are beaming troops all over the city and are slowly overwhelming the human defences forcing Weir to reactivate the self destruct sequence.
- Deus ex Nukina
- Heroic Sacrifice: Sheppard's plan at the end.
- Inhumanable Alien Rights: Sheppard repeatedly shoots Bob the Wraith in an effort to extract information, technically a form of torture.
- Jerk with a Heart of Gold: Col. Everett is a jerk whose tone is almost invariably condescending (especially towards Weir and other non-military personnel), who rather underestimates the Wraith, but he's also doing everything he can to protect Atlantis and the people within it, and acknowledges Weir's diplomatic skills.
- Nuclear Option: Col. Everett brings along nuclear space mines to destroy the hive ships when they reach orbit. Unfortunately, the Wraith see this coming and blow them up with asteroids.
- Please Don't Leave Me: Or rather "please don't leave us to die" between Elizabeth and Sheppard.Elizabeth: "John you can't!"Sheppard: "I have to and you know it."
- Pre-Sacrifice Final Goodbye: Sheppard and Elizabeth get a moment before he goes.
- Season Finale
- Some Call Me "Tim": Sheppard immediately names the Wraith prisoner "Bob."
- The Cavalry: Colonel Everett and his marines.