Through the Looking Glass by karate0kat is a crossover between Battlestar Galactica (2003) and Firefly. Starting early in the fourth season of Galactica and shortly post-series for Firefly, things become complicated for both parties when a Cylon attack forces the Demetrius to make a blind jump, resulting in the ship crash-landing on a planet just as Serenity is resting there to prepare for its next job. With most of the crew dead and the Demetrius useless, Kara and the other survivors join Serenitys crew in time for a particularly personal mission.
Through the Looking Glass provides examples of:
- Artistic Licence Biology: While the Galactica could never find a reliable way to test whether someone was human or Cylon without relying on Baltar, once he learns that Sharon isn't human Simon is able to identify a unique feature in her blood that distinguishes her from humans, although he concedes he might have missed it if he wasn't actively looking for a difference.
- Birds of a Feather: Helo and Kara share a moment of this after Kara learns that Sams a Cylon, as Helo is the only other person who can understand what its like to be in Karas position right now.
- Canon Welding: Galactica and Firefly take place in the same universe, and it is strongly implied that the Final Five had some ties to the Alliance as Sam recognises the interior of Serenity.
- Death by Adaptation: Hot Dog, Erin Mathias, Seelix, and other members of Karas crew on the Demetrius are killed in the accident that led to them crash-landing.
- Everyone Has Standards: When Kara learns that John Dadik named a planet after himself, she reflects that even Baltar never went that far.
- Fire-Forged Friends: The two crews had already tentatively agreed to work together after the Demetrius crashed, but after they team up to stop a gang of thieves trying to take Serenitys cargo and kill or rape the crew, even the revelation that Sharons a Cylon doesnt deter Mal and Zoe from affirming they will now consider the other crew their friends.
- In Spite of a Nail: The exact circumstances are different, but Gaeta still sustains a serious leg wound, although Simon is able to treat it quickly enough to prevent amputation even if Gaeta remains in a coma for some time.
- Internal Reveal: The reader was aware that Sam was a Cylon from the beginning, but the characters only learn it when Simon runs a blood test on Sam.
- It's All About Me: John Dadik, a double agent who helped the Alliance during the War, not only received enough money for his services to buy his own planet, but then went on to rename the planet after himself.
- Jerk with a Heart of Gold: Seeing Jayne work to save Jean Barolay, as well as acting somewhat protective of her in the aftermath, prompts Mal to muse that Jaynes tender moments are rare, but they make him subtly more tolerable.
- Mama Bear: Athena cant show it directly as Heras still on Galactica, but when Jayne calls her it after he learns that shes a Cylon, she shows him a picture of Hera to reinforce that she is not just a thing but a mother, soldier and wife, in that order.
- Sequel Hook: No sign that one will be written yet, but as the story concludes, Kara and the other Demetrius survivors have accepted the offer to join Serenity, Inara has affirmed her plans to leave the ship, and River is shown to be talking to Head-Six.
- Ship Tease: Jayne and Jean are hinted to be developing feelings for each other.
- Spared by the Adaptation: Jean Barolay has already lived longer than she did in the series, avoiding the Cylon encounter that led to her being killed by a traumatised Six and becoming part of Serenitys expanded crew.
- Spirit Advisor: Head-Six is talking with River Tam.