Stargate Atlantis S05 E10 First Contact (1)

"A new gate will open. A lost city will rise again."

Dr. Daniel Jackson arrives in Atlantis to investigate a hidden lab left behind by the rogue Ancient scientist Janus. Their discovery has attracted the attention of a mysterious group of aliens, who infiltrate the city. Meanwhile, "Todd" and a delegation arrive on the Daedalus to bring forward Dr. Jennifer Keller's gene therapy.