Olivia Swann revealed that NCIS: Sydney is "upping the ante" for season 3 with story lines you have to see to believe. "We have a treasure hunt. We have an alien abduction in the outback. We have a podcast cold case from years ago," Swann, who plays NCIS Agent Michelle Mackey on the CBS series, exclusively told Us Weekly of the new season. "We have a nanotech assassin. We have explosions up the wazoo. We have everything this season, and it's going to be so, so fun." Swann, 33, promised "more action, more drama, more fun" when the series returns on Tuesday, October 14. "The main thing for the characters is the past coming up to haunt us," she revealed. "And there is an overarching kind of conspiracy that somehow links to Mackey, and it's very, very interesting and very intricate." How Many 'NCIS' Shows Are There? It's a Long List Swann called each episode a "mini movie" because of how much they are packing into each story line. "It's kind of just mind blowing, and it's just so fun. I think that's the main thing about this season. It's just a fun, wild ride," she continued. "And we get to kind of tag along with this found family, these misfits who are just trying to keep people safe." Daniel Asher Smith/Paramount+/CBS When it comes to the season 3 premiere itself, Swann told Us her crew is back in Sydney after being in Darwin, a hot, tropical, outback-esque area of the continent, to end season 2. "Episode 1 definitely deals with the fallout of Darwin. Mackey trusted the wrong person, and she's struggling to now trust her gut," Swann teased, referring to her former friends-with-benefits Etienne (John Fabry) turning out to be someone whose humanitarian aid mission was aided by terrorists. "And so that's obviously not ideal when we have a terrorist situation going on and a lot of bombs going off." Olivia Swann Teases NCIS: Sydney's Season 2 'Mystery' and Mackey's Secret The season premiere, titled "Gut Instinct," follows the NCIS team in Australia as they investigate the disappearance of two U.S. Navy aviators "adrift in the Coral Sea [that] leads the team to expose a sinister terrorist plot," according to the official logline. Daniel Asher Smith/Paramount+/CBS "It's definitely a high stakes time pressure case for them to solve," Swann told Us. "We're seeing Mackey in real time, really having to kind of try and figure out this case that makes no sense, whilst also worrying that she could make the wrong decision again." 'NCIS' and 'NCIS: Origins' Crossover Explained: When Does It Air? She added, "The fun thing about this season is that the theme is very much the past comes back to haunt you no matter how fast you run. So that is very true for a lot of our characters, and Mackey, especially." The actress teased, "We really do see her being tested in ways that we never had before, and the repercussions of her past and her choices, which means that we see the cracks in her armor. We see the vulnerability that lies under all of her strength." NCIS: Sydney returns on CBS Tuesday, October 14, at 10 p.m. ET, following NCIS at 8 p.m. ET and NCIS: Origins at 9 p.m. ET.