Reunion sees Ronon (Jason Momoa) encountering some of his fellow Satedans and begins to toy with the idea of leaving Atlantis and rejoining his friends.

Written by Paul Mullie and Joseph Mallozzi, this episode first aired on 12 October, 2007.

The Satedans Ronon and Teyla (Rachel Luttrell – in a new costume to help hide her pregnancy) encounter are old friends, Rakai (Aleks Paunovic), Ara (Kyra Zagorsky) and Tyre (Mark Dacascos). But as Ronon falls in with them, it begins to appear that there is something more going on here.

They have been performing strikes on the Wraith, but when Sheppard’s (Joe Flanigan) team joins them on one of the missions, more is revealed. Ronon’s friends are working with the Wraith, to capture Atlantis’ people. They want help to deactivate the Replicators, and end the conflict that has erupted, thanks to McKay’s (David Hewlett) updating of the command code.

On Atlantis, Colonel Samantha Carter (Amanda Tapping) is settling into her new role as the new expedition head, taking over Weir’s (Torri Higginson) position. McKay initially thought it was going to be him. Carter bids goodbye to Earth, and Teal’c (Christopher Judge) sees her off. And when she sets up her new quarters, there’s a picture of O’Neill. Sam establishes her leadership style and authority pretty quickly.

Ronon has to confront his former friends, while his new ones are rescued all against the backdrop of a Wraith outpost.

Teyla isn’t the only character to get a new outfit, most of the main cast gets new expedition uniforms, but supporting cast, and Sheppard stay in their old gear.

A very solid, and enjoyable episode.

Doppelganger debuted on 19 October, 2007. It was written and directed by Robert C. Cooper.

This one feels a bit like the SG-1 episode Cold Lazarus when a crystalline entity takes over a member of the team and returns to Earth. This time out, it’s Sheppard. He’s interacted with a strange black crystal while on a mission. Upon his return to Atlantis, everyone seems to have moved to A Nightmare on Elm Street.

Everyone seems to be having nightmares, and featured in everyone of them is Sheppard, and not a nice, friendly Sheppard, but a darker, evil one. Sheppard later makes a quip about goatees, referencing the most famous evil twin trope.

Keller (Jewel Staite) has the most screentime she’s had in the series up to this point. I quitee like the way she interacts with Carter. In fact, Carter seems to be meshing with the other characters nicely, changing the show’s dynamic a little, but really tying the franchise together in a new way.

Sadly this is Heightmeyer’s (Claire Rankin) final appearance.

The episode also makes a number of references to pop culture, and also the franchise’s continuity. It actually works pretty well, and allows the series to do a kind of spooky story, while making it work within the constraints of the series.

So far, I am loving season four. I was sad to see Weir go, but love the addition of Carter, and the series just seems to be firing on all thrusters right now.