"Sometimes when a person is sick, it's important for them to fight. I want you to fight this, okay?"
— Dr. Janet Fraiser
Cassandra Fraiser becomes dangerously ill on her sixteenth birthday, and begins to develop psychic abilities as her condition deteriorates. SG-1 returns to her home planet, and suspect that Nirrti is involved when they find an abandoned Goa'uld laboratory.
Last appearance of Cassandra, although she continues to be mentioned afterwards.
"Rite of Passage" provides examples of the following tropes:
- Bratty Teenage Daughter: Cassandra's acclimation to life on Earth has turned her into this by her 16th birthday; she is reintroduced giving attitude to Janet for the crime of asking her daughter to have a slice of the birthday cake Sam bought for her, and she doesn't stop mouthing off to everyone around her until the very end of the episode.
- Continuity Nod:
- SG-1 returns to the planet where they first found Cassandra.
- Nirrti still has access to technology that can make her invisible, and the team use TERs to search for her on the base.
- Nirrti had been a prisoner of Cronos since Fair Game, but managed to escape in the chaos after SG-1 killed Cronos.
- Dangerous 16th Birthday: Cassie's powers and the fallout that come from them manifest on this day, but it's suggested that the retrovirus Nirrti implanted her with responds only to stimuli once the subject reaches physical maturity. It was Cassie's first kiss with Dominic that triggered the change, and her actual birthday was incidental.
- A Day in the Limelight: One of the few episodes with a character focus on Fraiser during her tenure on the show.
- Evilutionary Biologist: It's revealed that Nirrti was conducting experiments on the children of Cassie's planet in the hopes that their evolution would eventually produce a human advanced enough to be the perfect Goa'uld host.
- I Gave My Word: The heroes agree to let Nirrti go free in exchange for saving Cassandra's life, a bargain which they reluctantly honor at the end of the episode. Nirrti admits that if their positions had been reversed, she probably wouldn't have done the same.
- I Just Want to Be Special: Cassie seems to enjoy her new psychic powers a little too much and begs Fraiser to let the transformation run its course, despite knowing that it'll likely kill her.
- Madness Mantra: Cassandra repeatedly states that she "has to go into the forest".
- Mama Bear: Once she realizes that Cassandra can't be saved through ordinary medical means, Fraiser takes matters into her own hands by busting into Nirrti's cell and holding her at gunpoint, after knocking out the guard with a shot of morphine. To make this even clearer, Nirrti is only persuaded to help after Hammond informs her that the woman pointing the gun at her is Cassandra's mother.
- Nice Job Breaking It, Hero: By killing Cronus at the end of Season Four, SG-1 unwittingly gave Nirrti an opening to escape her captivity (as she'd been Cronus's prisoner since early Season Three).
- Not So Stoic: Fraiser's trademark unflappable professionalism cracks when the patient she's trying to save is her own adopted daughter.
- Obfuscating Stupidity: Cassandra lampshades O'Neill's habit of doing this when she mentions that he always calls the knights in chess "horses".Cassie: He always pretends he's not as smart as he really is.
- Put on a Bus: Cassandra never shows up again, although she does get a few brief mentions here and there in later seasons.
- Running Gag: O'Neill's explanation for how Cassie is able to move chess pieces with her mind is "magnets".
- Sensor Character: Cassie is able to sense Nirrti's presence while she's invisible, thanks to the naquadah in her blood. Sam also has this ability, but Nirrti is smart enough to avoid getting close enough to her to trigger her senses, having been foiled by Sam's goa'uld powers during their last encounter.
- Sequel Episode: To both "Singularity" and "Fair Game" (following up on the Cassandra and Nirrti storylines).
- Ship Tease:
- Daniel and Fraiser have a brief moment when he offers to support her and they sort of hold hands and stare at each other for a while.
- Fraiser and Carter also have several moments throughout the episode, over their shared love and concern for Cassie. The opening scene is the biggest example; anyone not familiar with the characters' actual relationships might think Cassie was celebrating her birthday with her two mothers, rather than her adopted parent and close friend.
- Surprisingly Realistic Outcome: With SG-1's assassination of Cronus at the end of Season Four, his entire domain was thrown into chaos. In that confusion, Nirrti (who's been held prisoner since "Fair Game") managed to get loose.
- Taking You with Me: A variation after Nirrti is captured and Cassie's death now looks inevitable. A completely serious Jack makes it clear that if Cassie dies, Nirrti won't be far behind her.
- Tranquil Fury: Hammond and Jack after Nirrti is captured (and the feeling's reciprocated by the Goa'uld).
- Transhuman: Cassandra gains an increased brain capacity and telekinetic powers, though she's returned to normal after Nirrti heals her.
- You're Not My Father: Cassie slings this one off to Janet a couple of times throughout the episode out of frustration with being kept in the base. Janet's hurt reaction makes it clear that this is the first time she's used such a low blow before.
