jennifer garner
Actor Jennifer Garner (L) and Chairman of STXfilms Adam Fogelson speak onstage at CinemaCon on April 24, 2018 in Las Vegas. Ethan Miller/Getty Images for CinemaCon

Las Vegas -- Jennifer Garner’s “Alias” days are behind her, but the action genre is not. It’s been 12 years since she starred on the TV series, and even longer since she stepped into the shoes of Marvel’s Elektra, but now Garner is back with a new action film, “Peppermint.”

On Tuesday, Garner appeared at STXfilm’s slate presentation for CinemaCon in Las Vegas to discuss the upcoming feature and to reveal her reason for joining the project.

The film follows Garner who plays a wife and mother-of-one that tragically loses her family to cartel violence. When she names the killers in court, she discovers members of law enforcement are corrupt and refuse to charge them, leading her to take matters into her own hands. Five years after the death of her family, she returns to the scene of the crime and kills the men she deems responsible for the killings.

“I loved ‘Alias’ and I loved her in it,” STXfilms Chairman Adam Fogelson said of Garner at Tuesday’s presentation. “We are even more enormous fans of Jennifer Garner as a person.”

After several years of playing roles in non-action titles, Garner said she decided to step back into the genre because the role felt right. “There is no bigger stake than your children,” Garner explained of her attraction to the project. “The thing about ‘Alias’ that made it so special was J.J. [Abram]’s script ... To do action just for the sake of action never made sense to me.”

To prepare for the role, Garner engaged in intensive training which included two workouts a day and instruction in both boxing and martial arts. She also reconnected with her stunt trainers from “Daredevil” and “Elektra,” which she said made her “giddy.”

Still, even with her training, Garner said she was nervous to perform some stunts. “I was more scared to do the fights and the jumps,” she admitted.

“Peppermint” is due to release in theaters on Sept. 7.