Suspicion

"Suspicion" is the fifth episode of the first season of Stargate Atlantis.

Synopsis
After another unexpected encounter with the Wraith, the fifth encounter in nine missions, the Atlantis Expedition can find only one explanation, there is a spy in the city.

Plot
The Stargate activates unexpectedly in Atlantis, and the shield is immediately raised. After they receive Sheppard's IDC, Dr. Weir orders the shield lowered. Despite several Wraith weapons blasts, everyone makes it through, though Dr. McKay gets hit in the face by the Wraith stunners. He received an overload to his nervous system, causing temporary paralysis. However, Weir has greater concerns on her mind. Being the fifth time out of nine missions that Sheppard's team has encountered the Wraith, she can make one conclusion. There is a spy in Atlantis.

After McKay has recovered, Weir calls a conference to discuss the situation, although Teyla was not invited as she is Athosian. Major Sheppard objects, but Sergeant Bates supports the decision, as he believes only an Athosian could compromise their position. Weir is more concerned about what to do. Bates wants to suspend Stargate activity, but Sheppard states that they need ZPMs to power the city, and more importantly, the shields when the Wraith come. So their primary goal is clear, find out the spy fast. Bates also wants to confine non-essential personal to a section of the city, but Weir says that's going too far. Instead, they create no-go zones, and Weir wants to set up meetings with all the Athosians on the base.

Outside, Teyla goes to see Weir, as she was unaware of the meeting. However, she is stopped by one of the guards, informing her of the new off-limit zones. Before she can learn more, Sheppard catches her and takes her outside for a word. He informs her of the potential security leak, and the new security measures put in place. Teyla is alarmed that they would suspect an Athosian, who have been terrorized by the Wraith for centuries. Sheppard manages to convince her it's only a precaution, and Teyla reluctantly agrees to cooperate.

Later, Weir is having her interview with Halling. She tries to ease tension by asking him about his son, but it does little to help. Halling believes that Weir no longer trusts his people, but she just states that honestly, they don't know who to trust. She proceeds to ask him about his offworld excursions. He confirms this, and states that on a couple of his outings, he visited some close friends. Bates jumps to the accusation that his visits coincided with Wraith attacks, but Halling takes up a defensive position. He is disgusted that they would be accusing the Athosians, and leaves the interview with anger.

Meanwhile, McKay and Zelenka are running diagnostics on the Puddle Jumpers. While working, McKay finds a command sequence that is new to them. Before he can go to reference it in the Ancient database, Zelenka accidentally actives the sequence. To their amazement, the roof of the hanger opens up, revealing a way for the jumpers to leave the city.

In their quarters, the Athosians discuss the new security measures. Halling feels that they have had to put up with it too long, but Teyla states that she feels that the measures Dr. Weir have taken are in the best interests of everyone on Atlantis. Despite this, Halling is still uneasy, and wishes to leave the city to another world, but it is obvious with all the Wraith around that this would not be possible. Teyla, having heard all of this, goes to see Dr. Weir for her interview. She insists that the Athosians are innocent, but also that they are all not as understanding as Teyla is. She also tells Weir about the plans for leaving Atlantis.

At about the same time, Sheppard and Lieutenant Ford are preparing to take a jumper out to take a look at the planet. On their trip, Ford wonders about the name of the planet, wanting to name in "Atlantica", when Sheppard reminds him about their agreement that Ford wouldn't name anything. While in high orbit, they discover land, and that is "really big"; approximately 15 million square miles. Bates wants to dump the Athosians on the mainland, but Weir isn't ready to make that decision. The decision soon falls out of her hands, as Halling comes to inform her that the Athosians wish to go to the land to start their new life.

As they are preparing to pack, Teyla visits Halling's quarters to have a word with him. She informs him that Dr. Weir has arranged for communications between them, if help is ever needed. After the more formal talks, Teyla and Halling bid each other reluctant farewells. Later, Teyla watches as her people go away, being separated from them for the first time in her life.

With the Athosians gone, the Stargate suspension is lifted, and Sheppard's team goes through to explore once more. They are on a historical anthropological mission, examining ruins around the Stargate. Also, Sheppard sends Teyla and Ford on a mission to try and contact the natives. Teyla wanders off alone after a bit as Ford's presence might be scaring the natives. Back at the Stargate though, the team encounter the Wraith once more. They manage to escape, but Teyla and Ford get left behind. As soon as they get back to Atlantis, a medical team takes Sheppard to the infirmary, as he was hit by a Wraith stunner. McKay insists on a rescue mission, but Weir doesn't want to mount one until they know more. Their discussion is soon cut off when the gate activates. Teyla and Ford are under fire of the Wraith, and after security is set around the gate, they drop the shield, and let Teyla, with an injured Ford, through.

Having seen these events, Bates is concerned that Teyla might be the spy, but Sheppard doesn't want to hear it. Bates gets dismissed, but still takes matters into his own hands. He take Teyla's things to McKay, and asks him to search them.

Sheppard visits Ford in the infirmary, where he is recounting the events. They match up with Teyla's story, proving that she did not directly help the Wraith in any way. However, McKay comes to talk to Sheppard. He has found something in Teyla's belongings. Her locket is a transmitter, broadcasting a sort of homing signal. Sheppard recounts how he found it for her on the caves on Athos, which leads McKay to the solution on the puzzle. The locket was activated by Sheppard when he gave it to Teyla, and she had no idea that she was helping the Wraith. Now that they know this information though, Sheppard has a new plan to use the locket against the Wraith. They are going to try and capture one alive.

After preparing themselves with an arsenal of non-lethal weapons, they set up their booby traps on the same planet where they found the ruins. Using the locket as a lure, they get the Wraith in position and set off flashbang grenades and ground explosives. They manage to down one Wraith, but he initiates a self destruct to prevent capture. Meanwhile, Teyla tracks down another one of the Wraith, and faces him in hand to hand combat. Sheppard manages to stun him with Wraith stunners, and capture their hostage before he activates his self-destruct.

Back on Atlantis, Teyla is going for a visit to the mainland, and Weir sends with her a message and apology to the Athosians. Teyla agrees to pass it on, and assures Dr. Weir that in her place, she would have done the same.

At the same time, Sheppard goes to question their hostage, who is agitated that he was captured. The Wraith threatens that he will feed upon Sheppard when he is free. Also, he informs Sheppard that his capture will only accelerate the coming of the Wraith, and with them, Atlantis' demise.

Background notes

 * John Sheppard voices the "Previously on Stargate Atlantis" announcement in the beginning of the episode.

Series continuity

 * Weir says in this episode that the Athosians have been living in the city for three months, indicating the passage of time since "Rising".
 * Sheppard says the discovered land mass has an area of 15,000,000 square miles. However in a later episode McKay says its "roughly the size of North America" which is about 9,450,000 square miles. This however could be covered by the fact that Colonel Sheppard said "You know, give or take." indicating that his statement of 15,000,000 square miles was merely a rough estimate.