On the streets of 17th century Paris, law and order is more a fledgling idea than reality, and the Musketeers - Athos, Aramis and Porthos - are far more than merely royal bodyguards for King Louis XIII; they are inseparable, loyal unto death and committed to upholding justice.
In the second season, France teeters on the brink of war with Spain, and the death of Cardinal Richelieu has left a void that could yet be filled by an even darker threat.
Meanwhile, the Comte de Rochefort has escaped from a Spanish prison and aims to establish himself at court. An old friend of the Queen, Rochefort is a strong-willed soldier who has suffered a terrible ordeal at the hands of his captors.
But the Musketeers soon discover that this supposed ally is not all that he appears...
Vividly evoking the grit and grime of 17th century Paris's mean streets, this crack team of highly trained soldiers fight for honour, for valour, for love, and just for the pure thrill of it.
Jessica Pope (Quirke, Burton and Taylor, State Within) is the BBC executive producer, Adrian Hodges is an executive producer and lead writer, and Colin Wratten (Inside Men, Waking the Dead) is producer.