An idyllic day instantly turns into the stuff of nightmares in a new trailer for “Kidnap.” Karla (Halle Berry) is playing Marco Polo with her son Frankie (Sage Correa, “Grey’s Anatomy”) at the park when he’s suddenly kidnapped. Karla is too far away to stop the horror from unfolding, but she’s quick to react by jumping into her own car and pursuing the vehicle Frankie’s been taken into. The ensuing chase ends with carnage on the road and no reunion between Karla and her son. His captor still has him.

Karla visits the police station to file a report but posters for other missing children convince her that she’s going to have to take matters into her own hands if she wants to save her son.

“Let me tell you something — as long as my son is in that car, I will not stop! Wherever you go — I will be right behind you,” she tells the kidnapper. And she means it. Karla is shown wielding a knife at one point.

“Being a parent, I understood this in a very visceral way,” Berry has said of the film. “I play an ordinary mom forced to act in extraordinary ways. I got to put in a little of what Halle Berry would do in this situation. That was fun.”

Berry won an Oscar in 2002 for “Monster’s Ball.” “Extant” and “X-Men: Days of Future Past” are among her recent credits. She’ll star in “Kings,” the English language debut of “Mustang” writer-director Deniz Gamze Ergüven. The drama — set to bow later this year — is set against the backdrop of the 1992 Los Angeles race riots.

Directed by Luis Prieto, “Kidnap” opens in theaters August 4.