Ep 18. The Gift

Teyla begins to have vivid nightmares about the Wraith. Soon this starts affecting her duties. She becomes easily distracted, causing Sheppard to order her to see Dr. Heitmeyer. The session leads Teyla to consult an Athosian elder about her past. The information the elder gives her leads the team to investigate a strange planet where Teyla and her father once lived.

What they find there, and what Dr. Beckett subsequently finds out about Tayla through blood tests, shocks the small group, who learn of Teyla's secret.