In her own Marvel stand-alone picture, the title hero, an ex-KGB assassin, springs into action after the events of “Captain America: Civil War.”

“I used to have nothing,” the title character, played by Scarlett Johansson, says in the first trailer for “Black Widow.” And “then I got this job, this family, but nothing lasts forever.”

Nothing except, it seems, the Marvel Cinematic Universe. The first entry in the series since the apparent finale, “Avengers: Endgame,” in April, this stand-alone spinoff flashes back to the events following the 2016 film “Captain America: Civil War.”

Johansson’s character, Natasha Romanoff, has been separated from her Avengers cohorts, although we see glimpses of Nick Fury (Samuel L. Jackson) and Hawkeye (Jeremy Renner). She returns to her native Russia and reunites with her makeshift former family — after engaging in some hand-to-hand combat with her “sis,” Yelena Belova (Florence Pugh).

Along with the parental figures Red Guardian (David Harbour) and Iron Maiden (Rachel Weisz), the ex-KGB assassin Natasha vows to take care of “unfinished business.” Naturally, it involves riding motorcycles, shooting guns and jumping out of helicopters.

“Black Widow,” directed by Cate Shortland, hits theaters on May 1.