Stargate: Atlantis: McKay & Mrs. Miller

Rodney's estranged sister Jeannie, who had given up on a brilliant career to raise a family, works out an important mathematical equation, which could be used to create unlimited energy by bridging parallel universes. Zalenka builds a mechanism based on Jeannie's proof. During the experiments, a foreigner, 'Rod', who looks exactly like Rodney appears from the parallel universe. Rod tells them that his universe is in danger. Everyone, except Rodney, likes Rod. Rodney thinks that Rod is a liar. He doesn't like Jeannie giving attention to Rod. Rodney and Jeannie have another round of sibling squabble. Zalenka and the others try to come up with a plan to send Rod back, but it is frought with danger.