Season 6 ends with a Callen-centric episode that finds the team traveling to Moscow to continue looking into the case of the oil tanker that went missing earlier this season. Their investigation also turns up some surprising revelations about Callen from both Hetty and Arcady Kolcheck, who returns for the episode. “There’s a fairly big reveal at the end,” executive producer R. Scott Gemmill teases. “Callen’s put in somewhat a precarious position because he has an opportunity to learn more about his past, but he has to focus on the task at hand more. So, he’s sort of torn between the two opportunities.” The “big reveal” comes courtesy of Hetty, whose past also becomes illuminated in a surprising way. “She runs into some old acquaintances and reveals something … that you wouldn’t have expected from Hetty,” Gemmill says. In addition, the finale will also introduce a female character who will return in a different capacity that will play into Callen’s life as well.