Despite the ever-present weight of knowing that Tom would sooner or later be departing for America, Mary spent the next few weeks happier than she'd been since Matthew was alive.

She and Tom worked side by side, running the estate and puzzling over how to raise the money to repair the estate cottages now her father had put the kybosh on the building development at Pip's Corner. They played with the children and took them for walks, subtly showing George the land that would one day be his and making sure Sybbie would remember her English home. They ate dinner with the family and socialised with neighbours in the county.

In between times, whenever they could snatch a few moments, there was lots of kissing and lots of lovemaking. Lots and lots of kissing and lovemaking. Tom was as good as his word at providing her with memories. There was barely a secluded part of the estate that Mary couldn't think about without a smile and a blush. Her initial shock at Tom's suggestion of making love in the office seemed a dim and distant memory.

And it was nothing short of a miracle that neither one of them had been caught sneaking to or from the other's bedroom in the middle of the night. There had been a close call one night when Tom had to divert to the nursery under the pretence of checking on Sybbie when Thomas Barrow had suddenly appeared at the end of the corridor like the ghost on the ramparts of Elsinore castle.

No, Mary had no complaints. She and Tom were on an even keel, avoiding any discussion of his upcoming move to Boston, focusing instead on the present. At least, she was. She knew he must be making arrangements, but she didn't ask and he didn't say anything.

Apart from the Boston problem, there was only one thing that bothered her slightly, popping uncomfortably into her mind now and then to niggle at her, and that was the issue of how very much she wanted Tom. Mary had expected the sheer intensity of their physical relationship to slacken off as time went by, but it hadn't. The pull between them was just as powerful now as it had been that first time.

At first, she'd assumed the sex was so good because she'd been celibate for so long then had such an unsatisfying encounter with Tony. She'd thought Tom was simply the lucky beneficiary of all that pent-up passion or that she'd been so frustrated, it had heightened her response to him. But they'd been scratching their itches together for weeks now and the fire had never dimmed. Her body reacted to his every touch just as fiercely as it had at the beginning. In fact, if anything, she craved him even more now. She couldn't get enough of him and, although they never discussed it, she suspected it was the same for him.

What bothered her and left her feeling slightly guilty was that while the physical side of things had been good with Matthew, they had never been this good. Mary didn't like to think about that too much, so she carefully boxed it up and stored it away, choosing instead to focus on the here and now.

And right now, they were in London for Rose's wedding, and the whole family and more were crammed cheek by jowl into Grantham House. That posed a problem for Mary, one that she was bound and determined to solve.

'Face it, Mary,' Tom said in a low voice as he stood opposite her, drink in hand, his back to the room. 'We might have to wait until we get home to scratch an itch.'

Mary pursed her lips in displeasure, surveying the inconvenient number of relatives milling about the place. 'I don't accept that, Tom. There must be some nook or cranny somewhere in this gloomy old house we can appropriate even for a short time.'

He smiled at her affectionately, amused by her determination to get her own way. 'Well, you know the place far better than I do.'

'Yes, I do. My room is next to Granny's, so that's out. If she so much as heard a man's footsteps outside my door, she'd be out to thrash him with her walking stick. You're next to Mama and Papa, so that's no good either. Far too risky,' she said, her mind ticking over. 'Right, here's the deal. I will find a suitable place to do the deed. Your job is to make sure you have the necessary supplies with you for when I succeed. It might turn out to be too spontaneous for my little device. I know how inventive you can be, Tom – and believe me when I say how much I appreciate that – but I don't think I can wait until we get home to have a proper scratch.'

Tom laughed halfway through a sip of his drink, choking a little and ending up having a small coughing fit as Mary looked on, smirking.

Edith came up behind him, patting him on his back in concern. 'Are you quite all right, Tom?'

'F-fine,' he stuttered, wiping his mouth and waving his glass at her. 'Just went down the wrong way.'

'As long as Mary isn't trying to poison you,' Edith said, with a barely concealed look of dislike at her sister.

Mary rolled her eyes in disgust at Edith's weak dig. 'Why on earth would I poison Tom? I like Tom. If anyone needs to be wary of me putting arsenic in their drink, it's you.'

Edith glared at her. 'That's so typical of you to say something so nasty.'

'You started it,' Mary shot back.

'Ladies!' Tom protested. 'Please. For Rose's sake, could you stop with all the sniping at each other while we're here for her wedding?'

Edith shot another quick, venomous glance at her sister. 'All right, I will, for your sake and for Rose's. But only if Mary agrees to retract her claws for the next few days.'

Tom cocked an expectant eyebrow at the elder Crawley sister. 'Mary?'

Mary sighed dramatically. 'Fine. For you, Tom, I will. Let's call a truce, Edith, until after the wedding.'

'Very well. Now, if you'll excuse me, I need to speak to Aunt Rosamund about something.'

Edith left them, picking her way through various relatives towards her aunt. Mary watched her go with a thoughtful look on her face.

'Do you know,' she said, 'I think Edith might have proved herself useful for once.'

'What do you mean?'

'I mean she's reminded me of something.'

'What?'

'The arsenic cupboard.'

Tom cast a sharp look at her. 'What? Surely you were joking?'

'Don't be silly. Of course, I was. Tempting as it may be sometimes, I won't be poisoning my sister any time soon. No, she made me think of the medicine room on the fourth floor. When we stayed here as children, Nanny used to take us there to patch us up if we hurt ourselves.'

'So?'

Mary gave him a smug smile. 'So, I may have just found the answer to our little problem. I'm sure it's still there. As I recall, it's only a small box room, so I doubt it will be being used for much else.'

'Won't the servants be around on the fourth floor?' asked Tom, doubtfully.

'I shouldn't think so. At least not until bedtime. As long as we time it right, they should all be downstairs in the kitchen or the servants' hall.'

'I'm not sure, Mary. It feels risky to me.'

'Fiddlesticks! It's perfect. It's not like any of the family will be poking about up there. We'll likely have the whole floor to ourselves.'

'You've made up your mind, haven't you?'

'Yes, I have. Come on, Tom, faint heart never won fair damsel. And I know you don't have a faint heart. You're still a rebellious socialist underneath it all.'

Tom sighed, knowing he was fighting a losing battle. 'When?'

Mary could barely contain her glee. 'After tea but before dinner. The servants will be busy transitioning between the two and everyone else will be resting or visiting someone or whatever it is they do when they're in London.'

Three hours later, Mary and Tom crept up the stairs, keeping a sharp lookout for anyone prowling the corridors. When they reached the fourth floor, it appeared deserted.

'I told you,' Mary whispered in triumph. 'Not a soul about.'

She stopped as she realised her heels were making quite a racket on the wooden floor, so different from the deep pile of the carpets on the lower floors. She bent down and yanked off her shoes, winking at Tom as she straightened up. 'Better safe than sorry. I'll be as quiet as a church mouse now.'

Gathering up her shoes, she grabbed his hand and towed him towards the medicine room, opening the door and quickly taking stock of it. On one side was a cabinet with a table and a chair next to it. On the other was a series of stacked boxes, none of which looked like they'd been touched for years.

'Perfect,' she said, making a beeline for the table. She dropped her shoes and spun round to grab hold of Tom's tie, using it to pull him with her as she backed up until her bottom pressed against the edge of the table.

He slid his hands under her bum and lifted her onto the table, his eyes twinkling. 'All right, you win. This will do.'

Mary gripped his tie and dragged him closer, hooking her legs around his hips and kissing him fiercely.

'I didn't have a chance to put my little device in, so you'd better have fulfilled your end of the bargain,' she said, desperately hoping he wouldn't let her down.

Tom grinned, reaching into the inner pocket of his jacket to pull out a small paper packet. 'I brought a supply with me from home. I knew we wouldn't be able to resist if we got an opportunity.'

Mary giggled gleefully. 'Oh, Tom, sometimes I can't tell you how much I love you and your talent for planning ahead.'

A strange look passed over Tom's face and then he fell on her neck, kissing, licking and nuzzling it, making Mary squirm and moan in delight.

And it was right at that moment that the door banged open.

'What, may I ask, is going on in -'

Mary froze, staring in horror over Tom's shoulder at Carson, who was staring back at her equally horrified, slowly turning bright red at the sight of Lady Mary Crawley in a lewd embrace with Mr Tom Branson.

In her arms, his face still buried in her neck, Tom didn't move a muscle in the vain hope that Carson wouldn't recognise him.

'Milady,' Carson said in a strangled voice. 'Mr Branson. I do apologise.'

Damn, thought Tom. There went that faint hope.

Carson shut the door then apparently stood outside it for a few agonisingly long seconds to recover his composure before they heard his footsteps retreating down the corridor.

Tom lifted his head and Mary wrenched her gaze from the door to look at his face. They stared at each other in shocked silence.

'Oh, my God,' Mary whispered. 'That was Carson… Carson saw… oh, heavens.'

Then to Tom's utter astonishment, she started to laugh. 'His face, Tom! Oh, my God, you should have seen his face!'

She dissolved into giggles as Tom stared at her, wondering if she quite grasped the complete disaster that had just unfolded.

'He was… he was…' Mary gasped, 'Oh, God, he was bright red, the colour of a p-p-post box! I thought he might burst a blood vessel! Oh, God.'

Then she was off again, laughing like she might never stop. Tom stroked his hands down her arms, trying to soothe her. Eventually, she calmed down, the giggles stuttering to a stop. She wiped the tears from her eyes and looked up at him.

'Oh, my God,' she whispered, eyes wide. 'Carson knows. He saw us.'

'Yes.' Tom nodded, still gentling his hands up and down her arms.

'He knows.'

'Yes,' Tom repeated. 'You'll have to talk to him.'

'Me?' Mary squawked, horrified.

'You're the only one that can salvage this. If I go to him, I really think he might take a poker to me. If we go to him together, all the servants will see, and we may as well have announced it in the drawing room. It has to be you.'

'Oh, God,' she moaned, burying her head in her hands.

'Well, it could have been worse,' Tom reasoned, striving to find an upside to all of this.

'How could it possibly have been worse?' Mary muttered into her fingers.

'Think about it, Mary. If he'd walked in five minutes later, he would probably have found me balls deep inside you, and I think that might have finished the old bastard off.'

Despite herself, Mary began to giggle again. Tom smiled and wrapped his arms around her, pressing a comforting kiss to the top of her head.