Must Aramis commit treason in order to help his old friend Marsac get revenge?

New episode, new adventure. Freshly back from chasing renowned explorer Émile Bonnaire across France as he tried to escape arrest, the Musketeers are summoned to secure a welcome ceremony.

King Louis XVIII's sister, the Duchess of Savoy (Phoebe Fox) is married to the Duke of Savoy (Vincent Regan), the ruler of a neighbouring principality that is a crucial buffer between Spain and France.

Savoy has come to Paris to discuss a peace treaty with the King that would guarantee France an advantage against Spain, but during the welcome ceremony, presided over by the King and Queen of France, a man hidden in the bushes attempts to assassinate Savoy. He fails, while Savoy's first minister takes the fatal bullet.

The Musketeers search for the killer and Aramis catches the man, only to discover that it is his old friend Marsac (JJ Feild), once a fellow Musketeer turned deserter.

Marsac had disappeared after a troop of 20 Musketeers sent into the principality of Savoy five years before to depose the Duke were massacred by an enemy attack that left Aramis and Marsac as the sole survivors.

Aramis' old friend has returned to seek revenge on all parties involved – he is convinced that Captain Treville, who sent them into the neighbouring territory, ordered the attack that killed the Musketeers. He begs Aramis for help, and eventually D'artagnan, Porthos, Athos and even D'artagnan's landlady Constance Bonacieux are roped in to help harbour Marsac.

There are many agendas afoot. The Duke of Savoy is an opportunist, and while he could be persuaded to side with France for his wife's sake, his anger over the attempted deposition and the failed assassination makes him a dangerous adversary.

Not only that, Savoy has reason to believe that his Chancellor, Cluzet (Simon Paisley Day) was kidnapped by the French during the deposition attempt and is now being held as a political prisoner of France.

Cardinal Richelieu and Captain Treville must work together to keep Savoy from going off the deep end, in particular making sure that Savoy does not find out where Cluzet is being held. Meanwhile, Treville has a secret of his own that he must come to terms with, which the Cardinal loses no time in poking fun at him for.

Then there is the Duchess, the King's sister. While she misses her brother, it is clear that she is in love with the Duke of Savoy and fond of her young son. She shows much more fortitude than the King's wife Queen Anne, and a certain ruthless streak not unlike that of Anne Boleyn (or at least the film adaptations I have seen of her).

The Duke of Savoy is a tough adversary in BBC's The Musketeers
The Duke of Savoy knows that he holds the future of France in the palm of his hand, so he can be as difficult as he likes BBC

All in all, this was an episode where politics and secrets reigned supreme. Peter Capaldi's Cardinal and Hugo Speers' Captain Treville provided the majority of the humour in the piece as the Cardinal mocks Treville for being so feeling and emotional about matters of state - "You're very sensitive for a man in the business of killing," was a line that particularly tickled me.

While I did miss Milady and seeing how the many possible romantic paths are enfolding for the Musketeers, I have to say that I continue to enjoy the show's format, whereby each episode seeks to take the viewer on a new, standalone adventure, whilst dropping small crumbs into the lives and pasts of the valiant Athos, Porthos, Aramis and D'artagnan.

It doesn't get staid – you don't feel like you're watching the same show.

You could pick it up anywhere in the series and still get the essential point, i.e. that this is a show about Musketeers, seemingly in period France (although they all sound way too English) and that they have their work cut out for them trying to do their jobs with honour while dealing with the machinations of those in power.

I am pleased to see that the Musketeers bond well together, and even when they face treason for harbouring and knowing of the whereabouts of the killer, they still band together to protect their friend.

This is what I was talking about in my review of the pilot episode, when I compared The Musketeers to children's cartoon Dogtanian and the Three Muskehounds.

The spirit of "all for one, one for all" is there. No matter what happens to them, they will always stand beside each other as brothers, and fight to protect the monarchs of France.

If Adrian Hodges can hold true to what the Musketeers truly represent, that sacred bond of a band of soldiers, and continue to sprinkle dastardly enemies and their secretive machinations through the show, then I will keep watching.

Hopefully though, next week we will see more of the personal lives of the Musketeers. They need to have a bit more fun, methinks. I hope for more of Milady, more female characters to match wits against the Musketeers, and that the tabards or frock coats finally make an appearance.