Slater (Christian Slater) makes his first appearance of the season. He's going to be a part of the operation from now on and it doesn't seem like he and Archer are getting along.
Slater tells Lana and Archer that they need to go to Buenos Aires (which Slater and Archer disagree about how to pronounce) to retrieve an asset who's been exposed. The name of the agent happens to be none other than Conway Stern who last appeared in the first season episode "Diversity Hire" and was revealed at episode's end to be a double agent and stole sensitive information to sell to the Chinese.
Slater explains that the gang formerly known as ISIS didn't have the whole story: Conway was deliberately feeding the Chinese false information.
En route to Buenos Aires, Archer discusses concerns with Lana about what will happen to their baby if they go on a mission together and both perish. Lana reveals to Archer that the baby would go to her family and Archer is upset that his mom wouldn't inherit the baby. This segues to the B-plot at headquarters where Mallory has, in fact, misplaced the baby.
When Archer and Lana meet Conway in Buenos Aires, the tension hasn't eroded any: Archer and Conway immediately break out into a fight. After things calm down, Conway walks them through the plan to retrieve a valuable disk from the Argentinean Intelligence Headquarters.
Archer (who qualifies as vaguely Hispanic-looking for the purpose of this episode) is to infiltrate the Buenos Aires HQ by impersonating an agent. Of course, the plan fails and Archer has to fight his way to safety.
At the end of the skirmish, Conway reveals he's a double-agent again and snatches the disk from Lana. He almost gets away with it but insults Lana one too many times and Lana takes out his hand again. Conway still gets away.