Set in a small town, the movie centres on a money-hungry woman whose big-city dreams failed and in order to land a high school crush, she uses a hapless man as a pawn in a get-rich-quick scheme that goes wrong, said The Hollywood Reporter.
The project is said to be in similar lines of "To Die For", Gus Van Sant's 1995 black comedy that featured a breakout performance by Nicole Kidman.
Brad Inglesby has written the script for "Nancy and Danny", which is being produced by Alexandra Milchan of EMJAG Productions, Indian Paintbrush' Steven Rales and Mark Roybal as well as Todd Field.
Mulligan, who last year co-starred in "Drive and Shame", will next be seen in "The Great Gatsby".