McKay discovers one of the Ancient Communication Devices that Daniel Jackson used to reach the Ori Home Galaxy, but accidentally activates it himself, and his Consciousness is sent into someone there. Dr. Weir knows that if the Ori get a hold of Rodney, learn of Atlantis, or are able to track the signal, that they will begin an invasion of the Pegasus Galaxy as well. Sheppard is elected, well offers, well insists, on using the Device to get Rodney back, with his Gene; he might have more control over the process. Arriving in the Ori Home Galaxy, he finds Rodney, and their relief at finding each other leads to a surprisingly physical manifestation for both of them, as well as a Heresy to the Ori.
Rodney McKay has always had a terrible relationship with his Mother, she never wanted kids, let alone a relationship with them, and that suits Rodney just fine, he’s a grown man, works for the US Government, and has no real desire to see her ever again. Rodney’s Sister Jeannie however, has always tried to make an effort with their Mother, and when she asks Rodney to come home for a visit, he begrudgingly agrees. What he finds is that their Mother has taken up with an Air Force Colonel, half her age. Rodney sees this man, this John Sheppard, as a nothing more than a gigolo, and if he actually cared about his Mother, he’d be worried, but she has a palpable distaste for her Son, something that John takes notice of, and doesn’t like one bit.
Okay I have seen only two Pern crossovers with SGA and I challange anyone that has read the books, or fanfictions, to come up with one that has to deal with fighting thread, harpering, or Holding. Must have a good plot, can be typical take over the world, but how are you going to do it, and what are you going to use? Remember that Dragon can't fight Dragon, and Robinton is dead.