And it is Natasha Romanova's past as a "trained killer" that she has to face up to in the form of the mysterious "Taskmaster," who may represent an evolution of her home country's top-secret assassin training program.
We see the new villain near the end in a striking clip of the Widow facing off against her enemy—who is obviously as lethal as she is.
Black Widow also stars Florence Pugh as fellow assassin and Romanova's sister Yelena Belova and David K. Harbour as Russia's answer to Captain America, the Red Guardian—a superhero who has gone to seed but is still deadly enough to take down an enemy one-handed.
One mystery in Black Widow is just why Natasha is on the run. Here's one official synopsis, which admittedly doesn't help:
At birth the Black Widow (aka Natasha Romanova) is given to the KGB, which grooms her to become its ultimate operative. When the U.S.S.R. breaks up, the government tries to kill her as the action moves to present-day New York, where she is a freelance operative.
This long-anticipated standalone—Marvel fans have sought a Black Widow feature since Johansson took the role—occurs just after events in Captain America: Civil War and hits theaters on May 1, 2020.