The Best Episodes of Stargate Atlantis Season 4

With a plan to potentially extinguish the Replicator threat, the Atlantis team must seek an alliance with a fleet of Wraith ships.

Director: Andy Mikita

Writer: Martin Gero

Teal'c visits Atlantis to counsel a headstrong Ronon, who is up for review by the I.O.A. But the two must work together when the Wraith invade the Midway space station in order to reach Earth.

Director: Andy Mikita

Writer: Carl Binder

Sheppard returns to Atlantis after a mission and finds the city abandoned, all systems dead -- and instead of ocean, sand dunes as far as the eye can see.

Director: Martin Wood

Writer: Paul Mullie, Joseph Mallozzi

Floating in deep space with the city's protective shield failing, the team must do all they can to keep Atlantis alive. A radical injury threatens Dr. Weir's life.

Director: Martin Wood

Writer: Martin Gero

Colonel Sheppard and his team embark on a risky mission to steal a Z.P.M. power module from the Replicators -- but must rely on a compromised Dr. Weir to succeed.

Director: Martin Wood, Andy Mikita

Writer: Carl Binder

When a virus causes amnesia in everyone except Teyla and Ronon, the Atlantis team must work together to find a cure before their memories fade entirely.

Director: Martin Wood

Writer: Alan McCullough

A mysterious drone crashes into Atlantis, indicating that the Replicators may have found the city. But when Elizabeth Weir appears, the team realizes that the probe is just a part of a bigger mystery.

Director: William Waring

Writer: Brad Wright, Paul Mullie, Joseph Mallozzi

The team finds their former Wraith ally's hive ship drifting in space, which leads them to a secret project that could turn the tide of a civil war.

Director: William Waring

Writer: Alan McCullough

The team is shocked when an old friend, believed to be dead, miraculously returns to them. Teyla plans an escape from Michael's captivity.

Director: Martin Wood

Writer: Alan McCullough

The team meets a man with extraordinary prophetic abilities, who gives them a dark prediction about Atlantis's future. The Wraith seek a new alliance with Atlantis in their war with the Replicators.

Director: Andy Mikita

Writer: Alan McCullough

Colonel Sheppard is captured by the inhabitants of a generational ship and their beautiful leader, who wish to use his ability to use Ancient technology for their own ends.

Director: William Waring

Writer: Paul Mullie, Joseph Mallozzi

Rodney McKay goes in search of his sister on Earth after she is kidnapped by the head of a powerful corporation.

Director: Andy Mikita

Writer: Martin Gero

As a mysterious new illness sweeps through the Pegasus Galaxy, Teyla is convinced by a vision that the father of her child is trying to communicate with her.

Director: Peter F. Woeste

Writer: Paul Mullie, Joseph Mallozzi

When a group of Ronon's people enlist the team's help in raiding a Wraith weapons facility, Ronon reconsiders whether his future lies in Atlantis or with his friends.

Director: William Waring

Writer: Paul Mullie, Joseph Mallozzi

An automated lockdown traps Atlantis personnel in various parts of the city, each of them hoping the others will come to their rescue.

Director: Martin Wood, Andy Mikita

Writer: Carl Binder

McKay, Carter, and Keller are trapped in an underground chamber while on an off-world mission, with no apparent means of escape.

Director: Martin Wood

Writer: Martin Gero

While on personal leave on Earth, Sheppard and Ronon learn that scientists have engineered a human-form Replicator -- who is now on the loose.

Director: Andy Mikita

Writer: Carl Binder, Joe Flanigan

Colonel Sheppard and Dr. McKay must protect a child princess on a pilgrimage before she can become queen, and learn that she has dangerous enemies threatening her life.

Director: William Waring

Writer: Martin Gero

During an off-world mission Colonel Sheppard unknowingly becomes host to an alien entity, which infects others in Atlantis and afflicts them with terrifying nightmares.

Director: Robert C. Cooper

Writer: Robert C. Cooper

During a visit to New Athos, Teyla and Dr. Keller find themselves on the run from a primitive tribe of warriors.

Director: Andy Mikita

Writer: Carl Binder