: The primary arc focuses on the escalated conflict with the Asurans (Replicators). This culminates in "Be All My Sins Remember’d," an episode featuring one of the franchise's largest space battles where Earth, the Wraith, and the Travelers form an unlikely alliance to destroy the Replicator homeworld.
: Teyla Emmagan spends much of the season searching for her missing people, who were kidnapped by the hybrid Michael Kenmore for his genetic experiments.
Stargate Atlantis: Season 4 – A New Direction Season 4 of Stargate Atlantis (2007–2008) serves as a pivotal turning point for the series, marked by high-stakes narrative shifts and significant changes to the expedition’s leadership.