Season Four has brought massive Replicator battles, the loss of favorite characters, and visits from old friends. But perhaps no episode has been so highly anticipated as “The Kindred,” the two-part episode that will dovetail into the season finale. And no episode has been kept such a mystery — until now.

The first solid plot information for “The Kindred” has arrived at GateWorld, courtesy of SCI FI Channel. The episode will bring major developments in Teyla’s search for her people — including Kanaan, the father of her unborn child. It will also see the return of a major threat from Atlantis’s past, as the humanized Wraith Michael and his genetic experiments (“Vengeance”) resurface.

Here is the network’s description of the first episode:

Dr. Keller is perplexed by a mysterious new sickness that has affected a number of planets in the Pegasus Galaxy and threatens to kill hundreds of thousands of people. Further study reveals that it is not a contagion but a human-engineered protein designed to kill a feeding Wraith. Col. Carter and Dr. Keller realize that someone is intentionally infecting the Wraith’s food supplies with no concern for the thousands of human carriers who are dying in the process.

Meanwhile, Teyla shares with Dr. McKay a vision she had in which Kanaan, the father of her child, was trying to send her a message that he is still alive. Now, more determined than ever to find him and the other missing Athosians, she convinces Sheppard to travel with her to a trading settlement in search for answers. What they find there leads them to startling discovery that no one could have anticipated.

We know from previous reports that the team discovers Carson Beckett (guest star Paul McGillion), friend and former chief medical officer on Atlantis, miraculously alive and well. Beckett died in an explosion one year ago (“Sunday”), and the circumstances of his return are not yet known.

In “The Kindred, Part 2,” explaining their friend’s return is the least of the team’s worries:

Everyone on Atlantis is surprised to learn that a friend, once thought dead, is miraculously back among them. A captive Teyla, meanwhile, is reunited with her missing fellow Athosians who have also been interned at one of Michael’s secret facilities. Ever hopeful that Sheppard will be able to mount a rescue, she begins to formulate a plan to ensure their escape, if he is able to find them in time.

“The Kindred” airs on Friday, February 22 and 29 at 10 p.m. (9 Central) on SCI FI! Learn more in GateWorld’s Season Four episode guide, and watch for exclusive new photos in the days ahead.