"I have no idea who I am, much less what I'm capable of."
— Vala Mal Doran
Vala is abducted by Trust, acting under the orders of the Goa'uld Athena, who hopes to retrieve knowledge once possessed by Qetesh from her subconscious memories of her time as a host. A botched rescue attempt causes the memory retrieval device to overload and erase all of Vala's memories; she manages to escape, but with no idea of who she is ends up taking a job as a waitress, and SG-1 enter into a race to find and retrieve her before the Trust do.
"Memento Mori" provides examples of the following tropes:
- Action Girl: Vala gets an opportunity to showcase her fighting skills when she takes down two random guys who decide to try and rob the diner she's working at without even breaking a sweat.
- Chained to a Bed: After Mitchell catches up to Vala — getting himself shot in the process — she takes him hostage, makes him drive to a motel and proceeds to handcuff him to the bed in order to get some answers out of him.
- Continuity Nod:
- The Goa'uld Athena is Ba'al's assistant Charlotte Mayfield.
- Daniel claims that he didn't give up on the belief that Vala was alive when she disappeared after destroying the Ori beachhead.
- Mitchell tells Vala that if she comes with him back to the SGC, they have a device he picked up on another planet that can help her recover her memories.
- Cooldown Hug: Daniel embraces Vala after talking her down and getting her to remember who he is at the end of the episode.
- Flashback: Vala is plagued by flashbacks of her time as a host as a side effect of the memory device Athena uses on her. The fact that she doesn't remember she was a host at the time only makes them more disorienting.
- Flashed-Badge Hijack: Mitchell commandeers a police motorcycle in order to chase after the bad guys making off with Vala by doing this.
- Greasy Spoon: Vala ends up working as waitress at one when she explains her situation to the owner after he catches her trying to leave without paying for her meal, prompting him to take pity on her and offer her a job.
- Hash House Lingo: Vala practices speaking like this while she's working at the diner.Vala: Okay. (Brooklyn accent) Dead cow on a turban, hold the yellow, extra spud mush.
- "I Know You're in There Somewhere" Fight: Daniel does this to Vala to try and stop her from leaving the warehouse and disappearing again while the others are fighting the Trust.
- In Medias Res: The pre-credits scene shows Vala working as a waitress for some unexplained reason and foiling the would-be robbers at the diner, and after the title sequence we flash back to the night she's taken three weeks previously.
- Instant Sedation: Averted; Vala is still semi-conscious and on her feet even after the sedative is injected directly into her carotid artery.
- Laser-Guided Amnesia: After the memory device malfunctions, Vala forgets all the specific details of her life and identity, but retains enough knowledge of social conventions that she's able to "pass" as a normal Earth-born human.
- Law of Alien Names: Lampshaded by Vala when Mitchell is trying to convince her she's an alien."Vala isn't a particularly alien name." (Reading the back of a twinkie): "Disodium guanylate. That would make a great alien name, don't you think?"
- Line-of-Sight Alias: Vala gives her name at the police station as "Valerie Todad" after noticing a children's drawing addressed "To Dad" on the wall behind the detective questioning her. Unsurprisingly, he doesn't buy it.
- Neuro-Vault: Athena has Vala kidnapped as she believes that the location of the Clava Thessara Infinitas, an Ancient "treasure map" is buried in her subconscious memories of her time as a host.
- Non-Indicative Name: Sol's Diner is owned by a man named Sal, much to Vala's confusion. He explains that he bought it from the previous owner, who was called Sol.
- Not a Date: Daniel insists that his taking Vala out to a fancy restaurant is nothing more than "two friends and coworkers out for dinner". No one really believes him.Vala: Oh, I've watched enough of your television to know what a date is, Daniel. It's a romantic event typified by dinner, a movie and/or karaoke, and usually culminating in a night of...Daniel: Okay, this is definitely not a date.
- Not What It Looks Like: Said by Mitchell when the rest of the team find him chained to a bed eating snack cakes in his boxers.
- Once Done, Never Forgotten: Carter laughs at Mitchell for losing his pants again.Carter: I just think it's funny how you're always losing your pants.Mitchell: I'm not always losing my pants. It's happened twice. Twice is not always.
- Only a Flesh Wound: Mitchell is shot in the upper arm by one of the Trust operatives who take Vala, and while he's obviously in a lot of pain he's able to drive a car okay, and seems to be mostly fine after Vala administers some DIY first aid using a bed sheet.
- Perp Sweating: Daniel invokes this by deliberately leaving the one Trust operative the team manage to capture alone with Teal'c in the interrogation room. The guy even says that he knows Teal'c is only there to intimidate him, and Teal'c still manages to get the information out of him in about two minutes flat.
- Self-Destruct Mechanism: The warehouse where Vala is taken at the beginning of the episode is rigged to explode in the event that it's ever raided.
- Silent Whisper: Teal'c whispers something to the Trust operative he's interrogating; the audience doesn't hear what it is, but judging from the guy's reaction it's obviously horrific.
- Sixth Ranger: Vala finally becomes an official member of the team when she gets her SG-1 patches from Landry at the end of the episode, making them a true Five-Man Band for the first time in history.
- Ship Tease: A lot of it for Daniel/Vala. In addition to the matter of their not-date and the Everyone Can See It reactions from the other characters (including Landry), Daniel is the only one who manages to get through to Vala during their emotional confrontation in the warehouse, and while Vala remembers each member of the team sitting around the briefing table in a flashback, she also has an additional memory of just Daniel on his own, standing next to her in the elevator.
- Shirtless Scene: Mitchell spends quite a while shirtless and pants-less after Vala steals his clothes and handcuffs him to a bed.
- Strapped to an Operating Table: Vala wakes up this way after being taken from the restaurant.
- Super Window Jump: This is how Vala escapes the warehouse as the two sides are shooting at each other despite the fact that there was an open-door mere feet from the window.
- Tired of Running: Daniel claims that this is the reason Vala chose to throw her lot in with the SGC while he's trying to convince her not to run away again.Daniel: If I let you go, I know you're going to make yourself disappear. You've been running so long, it's almost second nature to you. You don't remember it, but you made a decision to stop running. It's over. And now it's time to come home.
- Work Off the Debt: Ostensibly this is the reason Sal gives Vala a job at his diner, though in reality it's more for her benefit than his.
- You Wouldn't Shoot Me: Daniel pulls this on Vala when she threatens to shoot him if he doesn't let her leave.Daniel: You don't remember who you are, but I do. You won't shoot.
- Whatever Happened to the Mouse?: It's never revealed if Vala ever contacted Sal or Detective Ryan to let them know she was alright.
