Lucius Alexander Plantagenet Cary, Master of Falkland (born 1 February 1963) is an English screenwriter, producer, and ex-soldier.
Cary was born in Hammersmith, to Lucius Viscount Falkland and Caroline Butler. He grew up in Chelsea, where his neighbours were actors André Morell and Joan Greenwood. He knew from the age of twelve that he wanted to work in the film industry. He was initially educated at Westminster School, but was expelled before his A-levels, and sent instead to Loretto in Scotland. He left with unremarkable grades and, after a brief stint as a runner in a New York theatre, joined the army on a whim: "I had a bet with a friend who didn't think I could do it, but I loved it. Having been a total pain in the neck about authority at school, I took a perverse enjoyment in being given instructions and carrying them out."
He graduated from Sandhurst Military Academy in 1985 and was posted to Northern Ireland during the height of the Troubles. He saw active service during the Gulf War, in which he was attached to a company of American marines.
He left the military shortly after the war, and went to Hollywood to pursue a career as a screenwriter. After a decade of little success, he achieved a spot in the writers' room for the first series of Lie to Me in 2009. He later became a writer and producer for Homeland, and has also worked on The Riches and In Plain Sight.
In 2013 he became engaged to American actress Jennifer Marsala, a cast member in Homeland. The marriage took place in Somerset on 31 December 2013. He has a son, Lucius (born in Los Angeles on 6 February 1995), from his first marriage to Linda Purl, as well as a natural son, Sebastien (born 2004).
He appeared in the BBC program The Gift on 10 February 2015, in which met a fellow ex-soldier who wished to thank him for saving his life.