Quinn skips a mandatory visit to the gun range after getting a "911" text from her mother -- whose only emergency, as it turns out, is where to position the pansies in the garden she's sprucing up. But while Quinn's at the house, her mother reminds her that it's her father's birthday the following day and invites her to a dinner celebration, which will feature Marie's special.
While Gibbs (Mark Harmon) is completely understanding about Quinn's absence, Torres (Wilmer Valderrama) is nosy about where Quinn was and it's clear that Quinn wants to keep this particular mission a secret from her colleagues.
But that plan backfires when Marie shows up at the office to see firsthand where the magic happens. She takes quite a shine to Torres, despite being in a panic because her crockpot has gone missing and how else is she supposed to cook the 12-hour ribs?
Meanwhile, adding a bit of levity to the episode, the NCIS network gets hacked so everyone's cell phones get confiscated -- except for Gibbs, who doesn't have a smartphone to begin with.
Torres admires the fact that Marie is an "original cougar," but Quinn sets him straight, explaining that her mother is "nuts" and she refers to her as "Marie" because she's basically the mother in the relationship. After hearing that, Torres is convinced that there's something deeper going on and that Quinn is hiding a family secret.
It turns out, he's right. When Quinn arrives at her mother's house, she finds it filled with smoke, with the alarm going off. Quinn is further alarmed when she sees three place settings at the table, and gently reminds her mother that her father died three years ago. Marie seems shaken by the "news," but puts on a brave face and acts like she knew the whole time -- while Quinn realizes that her mother's memory lapses may be a symptom of a much more serious issue.
While looking at photographs in a more lucid state, Marie realizes that she's going "senile," just like her own grandmother did. She's been forgetting things for a while, and is worried that she's going to one day forget her own daughter or get to the point where she's a burden to Quinn. For now, Quinn says she refuses to put her mother in a nursing home.
Later, Quinn and Gibbs go on a private outing to the gun range, where Quinn laments the fact that her dementia has come on so quickly and says that she plans to move in with Marie to take care of her.
NCIS airs Tuesdays at 8/7c on CBS.