The first season of Downton Abbey premiered on September 26, 2010. The first episode was set in April 1912. The series follows the lives of Lord Crawley, who is the Earl of Grantham, his family and their servants.
In season one, the heir to the Earldom dies on the Titanic. Only a male can inherit the estate because of an entail. Lord Crawley only has daughters, so a distant cousin, Thomas Crawley, becomes the new heir. Thereafter, some of the family members work to break the entail; the Earl's daughter, Mary Crawley, marries Thomas Crawley; and Sybil Crawley, another daughter, dies of eclampsia. The servants also experience ups and downs throughout the season, including marriages, promotions, unplanned pregnancies and criminal prosecution.