Stargate Atlantis: Blood Ties

Publishers summary
The Atlantis team return from the Pegasus Galaxy to investigate a Wraith sighting on Earth. Teaming up with members of SG-1, they soon discover that the Wraith aren't the only monsters stalking human prey.

Sonny Whitelaw
Set near the end of Season 3, the Atlantis team return from the Pegasus Galaxy to investigate a Wraith sighting on Earth. Teaming up with members of SG-1, they soon discover that the Wraith aren't the only monsters stalking human prey.

This is not a crossover with SG-1, however it is set at the end of Season 10 SG-1. We've brought on board Daniel Jackson because we've returned to Stargate's mythological roots. Myths and legends form the backbone of the Stargate franchise, so this seemed like a fitting farewell to ten years of SG-1 while still remaining very much an Atlantis story.

Elizabeth Christensen
A series of horrific ritualized killings sends the Atlantis expedition on a mission to a rarely investigated planet: Earth. When Stargate Command discovers that the cult-like group committing the murders has its roots in a genetic anomaly related to the Wraith retrovirus, the search for answers spans two galaxies. While his team explores a Pegasus planet where Ancient research resulted in other fantastical evolutions, Colonel Sheppard joins forces with SG-1’s Daniel Jackson and an FBI profiler who keeps everyone guessing—all to halt an impending disaster that threatens to alter the very humanity of the residents of Earth.