The Korrasami fans won't let us forget this.
Korra returns to Republic City disappointed in her failure to defeat Kuvira at Zaofu, but she's supported by those closest to her. After getting her fantastic new outfit (the character designs in Avatar and Korra have always been great) she meets up with her friends Asami and Mako. Her reunion with Asami also leads to some blushing when Korra is complimented for her new hair. The creators appreciate that there is a vocal contingent of Korrasami shippers, so it's a nice nod to them.
Her reunion with Mako is less exciting, but as all three settle in (with unexpected guest Prince Wu), things start to get shaky. It might be easy to be frustrated with Korra's friends for criticizing Korra being gone for so long, but she was gone for longer than she even knew Mako, Bolin, and Asami. Adding in she lied about her whereabouts for the last six months or so and that she only wrote to Asami, and her friends' frustration is a bit more understandable.
After Wu is kidnapped by some benders from the Earth Empire, Korra uses the spirit vines spread throughout Republic City to find them, a trick she learned from Toph in the swamp. After rescuing Wu from a train, the group reconciles their differences and admit that after so long it makes sense they would need a moment to fall back into their old friendships.
Wu gets dropped off at Asami's home, where Mako and Bolin's family has been residing for three years, and it's a perfect match considering the dedication Mako's grandmother had for the Earth Queen. And now that Korra is back with Asami and Mako, we might start the run to the final confrontation with Kuvira and the end of the series.
Bolin and Varrick need their own show.
The world of Avatar is pretty much certainly finished after Korra is over, but Bolin and Varrick are so good together, it's kind of a shame we have no hope of a series or something for these two. Making their way through the Earth Empire, they run into some refugees from one of Kuvira's reeducation camps. Their revelation that the camps are actually prisons for dissenters and those who aren't natives of the Earth Empire is sobering for Bolin, who contributed to building the Empire with the hope that he was helping people.
Luckily, by the end of "Reunion" he gets to help the refugees. After Varrick and Bolin fail to get the group through an Empire check point, a fight breaks out. While a rather simple fight scene for this series, it's a fantastic exhibition of Bolin's skills as a fighter. He manages to pull off some great stuff and handle three of Kuvira's mecha tanks while Varrick uses his skills as an engineer to shut them down. After Varrick Tony Stark's a way for he and Bolin to escape, Bolin turns around and saves the refugees, later apologizing to them for what the Earth Empire has done.
At the very end of the episode, we see Kuvira ordering a group to chop up and collect the spirit vines of the banyan-grove tree in the swamp. The very swamp where Toph Beifong has been hiding out in. The swamp that Toph is constantly connected to in entirety. It looks like her story isn't over and we may actually will see the Blind Bandit throw down in the final season of Legend of Korra.
Bottom line: A simple episode that plays out perfectly well and paces the season for the final run to the end.
Recommendation: This isn't a crucial episode so you can skip it if you like, but I doubt anyone keeping up at this point is skipping anything.