Paris is a disgusting city. It is riddled with lice and littered with criminals. So it is only fitting that I should be here. I have no money, apart from five deniers. I had ten, before I bought a drink. That's where I am now; sat in the corner of the inn, with my hood pulled above my head. They know me as the Phantom Shadow here. In Paris, I am notorious.

I am an assassin. Many hire me to kill, when they are too cowardly to do it themselves. I have murdered unsuspecting husbands for abused wives. I have murdered frightened wives for cruel husbands. Then they pay me, and my pouch becomes full to the brim with coins. After I have killed a few people, I lay low for a while, and spend my livres on somewhere to sleep for a few nights.

I do not wish to draw attention to myself. It seems some people have other ideas.

The door to the inn opens, and four pairs of boots enter. 'I'm seekin' the Phantom Shadow,' announces a booming voice.

Snarling, I get to my feet. Secrecy is apparently out of the window. 'And you have found him! What is it you want?' Keeping my hood up, I approach the four men, my glass still in my hand.

Musketeers. The very sight of them makes my skin crawl. My free hand reaches for the dagger in my belt, ready to attack. Rule number one: always be prepared.

'Treville, Captain of the Musketeers, wishes to see you,' says another. This Musketeer looks older and wearier than the others. 'We are to take you to the Garrison immediately.'

'I will not go anywhere with you,' I bite out a reply. 'You will leave and I will go to your Garrison alone. I do not need an escort.'

The dark-skinned Musketeer scoffs. 'And how do we know you will come?' he asks in his booming voice.

Slowly, I take the dagger from my belt, and point it towards him. 'Take this,' I say. 'When I leave the Garrison, you will return it to me. If I do not come, you are welcome to keep it.'

The Musketeer is wary, but he takes the dagger. 'Very well,' he says, and he and his three companions leave the inn. I take a drink of the alcohol and grimace. Disgusting. Still, I stay to finish the glass before I even bother making my way to the Garrison.

Blending in with the Parisians is easy when you know how to act. Rule number two: keep your head down and don't talk to anyone.

I don't often steal – people are poor here and there is no enjoyment in taking money from those who need it – but I am low on funds so I pocket four sous from unsuspecting market customers. I make it to the Garrison a little quicker than I expect – I hoped I'd be able to make them wait – and I stand inconspicuously in the archway, watching as one of the Musketeers I encountered at the inn walks across a wooden platform and then down the stairs.

I step carefully out of the shadows. 'Is this Treville's office?'

There is a reason I am called the Phantom.

The Musketeer looks more than a little surprised to see me. His dark eyes widen, and his mouth forms a small o. He seems speechless for a few moments, and then says bluntly, 'I didn't expect you to come.'

'Well, I'm here,' I snap in reply, 'now is that Treville's office or not?'

'Yes, yes, of course, monsieur!'

'Very good,' I say, and storm past the Musketeer. I turn Treville's doorknob silently and step into the room.

'The Phantom Shadow,' greets Treville without looking from the papers on his desk. 'You have made quite a name for yourself.'

'I am aware,' I reply irritably. What is it this man wants?

'I must ask a favour of you,' he says, turning over one paper and dipping his quill into the open ink bottle to his right. 'I would like you to accompany my Musketeers on a mission to Orléans. There is a revolt the King would like to be quelled.'

I snort. 'And what makes you think I am going to go on any missions? I am not one of your Musketeers and I will not do as you tell me like some obedient schoolchild. If you want to make use of me, you will have to try harder than that.'

Treville frowns, puts down his quill, and looks up. Ink drips onto the paper. 'You will, of course, be rewarded for this work. I will provide you with a roof over your head, as well as hot food, for a month here at the Garrison. There will be no price for you, good sir.'

'Nothing about me is good, Treville,' I reply, narrowing my eyes at the Captain. I should reject his offer. The Musketeers do not like me. They do not trust me. There are not many people who trust me here. But I am tempted; if I cannot find anyone in need of an assassin, then I do not earn any money, and I am almost penniless. As easy as it is for me to steal, I will not become a thief to get by. 'We have a deal, Captain. When do we ride?'

'Tomorrow morning,' answers Treville. He rises from his seat and says, 'Let me introduce you to the Musketeers who will be accompanying you … although I am sure you have already met them.'

I follow him silently into the courtyard, where I am re-introduced to the Musketeers who ruined my day at the inn. Wonderful.

The dark-skinned man is named Porthos, and his older, wearier companion is named Athos. The Musketeer I surprised is called Aramis. And then there is the youngest, newest Musketeer. I cannot help but stare. I should not recognise him, but I do. My hands are shaking. It cannot be …

I try to forget about him. But all night I toss and turn, thinking about the young d'Artagnan. Twenty years and I have not forgotten. I merely pushed it to the back of my mind all these years. But the name … it has to be him.

I get barely any sleep that night, and am exhausted when I finally get on a horse. I amble silently after the four Musketeers, and it is only when we are out of Paris that somebody talks to me.

'What's your name?' asks Aramis. 'Apart from the Phantom Shadow, of course.'

'As if I'd tell you that,' I say. The horse whinnies. I do not see the point to riding. Things are much easier on foot. 'Would you tell me yours? I know it isn't Aramis.'

'Touché,' he murmurs, and I smile in satisfaction.

There is another question, this time from d'Artagnan. 'Won't you take your hood off? Or must you always remain secretive?'

'Very well,' I say before I can stop myself. I am weak. I cannot say no to him. The hood comes down, revealing my dark hair and soft brown eyes. My appearance contradicts who I am supposed to be. There is too much kindness in eyes that have seen so much cruelty. 'And yes, I must always remain secretive. It may not be obvious to you, but there are people who would kill me if they knew who I was.'

'Las' time I checked, people wanted to kill you anyway,' says Porthos gruffly.

I do not reply. It is best that I keep quiet. Once this job is over, I don't have to have anything to do with these Musketeers. I don't have to speak to them anymore. They are far too intrusive and curious. But I see why. Rule number three: never be satisfied until you know all the answers.

Orléans seems years away from Paris, but I know what a long journey truly feels like. Still, I don't say no when Athos suggests a break. We dismount and sit in the shade of a large oak tree. I take a well-needed drink of water. Aramis takes off his hat and then, to my surprise, his shirt. I quickly look away, but it would be wrong not to admit that I'm a little bit curious, so I turn my gaze to him.

My face flushes and I urgently pull my hood back over my head. He is deeply muscular, making him look even more attractive than he already is. He is Spanish. The fact is on the forefront of my mind. If our lives had been different, I could have married him.

But here I am. I'm stuck on a mission with some obnoxious Musketeers, d'Artagnan knows nothing of me, and my life feels like eternal Hell.

Really, it can't get any worse than this.