For the Stargate Timeline, it happens after Stargate Atlantis 4×3 and the Stargate Continuum movie.
For the Doctor it occurs after the first Star Trek (2009) reboot universe fanfic on this site which can be found here.
SPOILER: V: The Original Series.
What you need to know:
“The IOA (International Oversight Advisory) has set up a top secret base on the moon powered by a ZPM (Zero-Point Module) – an ancient power source. Stargate Command has commissioned special crafts called Eagles and a Stargate – a ring-like device created by the Ancients able to send people through a wormhole – but one without a protective iris. A separate section on the moon houses a super-hadron collider. A mysterious hyperdrive in the catacombs of the moon has been activated, catapulting the moon to an unknown area in space.The moon ended up sliding through different parallel universes..
Meanwhile back on Earth-777, another moon has just materialised in the place of the missing moon. Aboard the moonbase are reptilian aliens known as the Visitors. They had attempted to bombard earth’s Stargate but failed thanks to the iris.
The Doctor is an alien explorer through time and space, going to amazing and terrible places in the universe, armed with his fantastic sonic screwdriver. The Tenth Doctor is currently travelling with Spock Prime.”
Shots were heard. The Alpha encampment which was the only trace of civilisation on this parallel earth was being attacked. But by whom? Wasn’t all of humanity on this earth dead ?
Victor looked up towards the sky and saw an army of flying invaders.