What is Line of Fire based on? NBC's thriller grew out of a president's daughter's own life
The First Daughter in Line of Fire goes by the codename Sparrow, and one of the show's producers spent eight years answering to Twinkle.
Line of Fire premiered on NBC on September 21 and airs Mondays. Joshua Safran created it, and Jenna Bush Hager, the Today co-host and daughter of George W. Bush, is an executive producer. Peter Krause plays Mike Hollingsworth, a senior Secret Service agent, and Hope Davis plays his estranged wife, Jane, a U.S. marshal. Their grown children work for the FBI, the Justice Department and the Secret Service. One son, Micah, played by Tommy O'Brien, is assigned to protect the president's daughter.
How it started
At a children's party. Bush Hager told the story on Today With Jenna & Sheinelle in August: she and Safran "were talking actually, at my sister's kid's birthday party."
The family-of-agents idea came from Safran's side. Bush Hager said the concept is "kind of based on somebody that he knows." What she brought was the view from inside the protective bubble.
"I had the Secret Service for eight years," Bush Hager said.
Those were the years of her father's presidency, from 2001 to 2009, which covered her college years and her early twenties.
What comes from her life
The show is built around the people doing the protecting, and that's the part Bush Hager knows best. She told Woman's World where that comes from: "I had secret servicemen who would leave their family to protect mine."

Here's where her experience shows up:
- agents who protect other people's families and have families of their own;
- the First Daughter, Sydney, played by Savannah Lee Smith, and the young agent on her detail;
- the procedure, checked by a former Secret Service agent the production hired as a consultant.
Sydney is Sparrow on the show. Bush Hager's own codename, she revealed on Today in 2020, was Twinkle, and her twin sister Barbara's was Turquoise, for her eyes.
Bush Hager has admitted that "Twinkle" came with a problem: "some people got confused with 'tinkle.'"
What's made for TV
Most of it. The show is a thriller, and its plot, a conspiracy aimed at federal agents, comes from the writers' room. Bush Hager has been upfront that Safran set the limits early.
"Josh was like, 'Listen, some of it has to be made for TV,'" she told Woman's World. "But we'll also have some real truth to it."
She may also turn up herself. Bush Hager told Good Housekeeping there "may be a Read With Jenna, first lady situation" coming this season, a nod to her book club.
The stories she hasn't put on screen yet
Bush Hager's own run-ins with her protective detail are lighter than anything on NBC. In first grade, she faked her own kidnapping, with a story about "a man in a van with some puppies and some candy," because she'd stayed late at school and was afraid her mother would be mad. Her mother saw through it. The Secret Service didn't, and she had to go apologize.
In college at the University of Texas, she had friends hide her in the back of a car to get past her agents so she could see a football player she was dating. She told Today it was "the only time I escaped them, and then we broke up soon after."
Previously we wrote: What is Paris Has Fallen based on? Gerard Butler's name is all over it — just not in the cast list