“You are being charged with 27 breaches of the Official Secrets Act,” Judi Dench is told in a trailer for “Red Joan.” Retired and living a quiet life in the suburbs, Joan Stanley (Dench) is shocked when she’s arrested at her doorstep for alleged misdeeds of the past. She’s adamant that she’s done nothing wrong, but authorities are convinced she provided intelligence to Communist Russia.

“Red Joan” kicks off in 2000 and travels back in time to 1938 when Joan, played by Sophie Cookson, was a student at Cambridge University — and law enforcement first started a file on her. “The world was so different then,” she says. “You have no idea.” But officers do have an idea of how Joan was politicized — she was “known to consort with Communists,” and the trailer shows her getting close to one in particular.

After graduation, Joan lands a job at a top-secret nuclear research facility during WWII. It’s there that she realizes just how close the world is to the brink of mutually assured destruction — and is forced to make a decision that could affect the fate of humanity.

Dench won an Oscar in 1999 for “Shakespeare in Love.” She’s also received nods for “Philomena,” “Notes on a Scandal,” “Mrs Henderson Presents,” “Iris,” “Chocolat,” and “Mrs Brown.”

“Red Joan” made its world premiere at the 2018 Toronto International Film Festival. The film hits UK theaters April 19. A U.S. release date has yet to be confirmed.

Check out the trailer to see Joan be confronted by her son, who is beginning to doubt if anything she ever told him is true, and if she was indeed “part of some Cambridge spy ring.”