The Musketeers is a 2014 BBC television programme based on Alexandre Dumas' 1844 novel The Three Musketeers. As in the original story, the series follows d'Artagnan in 17th century France as he meets and then works alongside three members of the King's Musketeers: Athos, Aramis and Porthos, commanded by Captain Treville. Together, they protect the King and Queen from threats and are later forced to protect themselves.
Beyond the story's setting and main characters, though, The Musketeers has little to do plot-wise with the French novel. The show's creator, Adrian Hodges, describing his work, said, "It's a case of taking everything you love from the novel, and just twisting it a bit further for a modern audience. [...] You get that comradeship, you get that humor that you often find with men in battle together, you get romance."
The Musketeers being historical fiction, some real history does play into the plot. Peter Capaldi, who plays the series' main antagonist, Cardinal Richelieu, First Minister of France and advisor to the King, describes the political situation at the time: "France is in danger, really, of succumbing to the power of Spain or Rome, or indeed England. He believes that it's more important than anything else that France becomes strong." Richelieu keeps King Louis XIII under his thumb, and hates his Musketeers with a passion.