Sorry for the delay getting this chapter up!

And to the guest reviewer who protested Beckett's ordering of a chicken burger in the previous chapter, I will continue to fight the good fight for the humble chicken burger. Admittedly, I am not a former nor present New Yorker and there is a part of me that mourns missing the opportunity to have Castle tease Beckett about it. (Also, your review made my day.)

Rick didn't get much sleep that night. Nikki is Beckett, he kept thinking to himself, over and over again, unsure of what to do with that information.

Should he tell her? That had been his first instinct. You'll never believe it, he could have replied to her message, but I know who you are, Nikki! And you know who I am! And then that could have lead to some fun guessing game where he would make her figure out who he was based on clues he gave her.

But would that have really worked? With Beckett being Beckett, she would most likely close up instead. Stop replying to his messages. Probably freeze him out at work, being embarrassed that she'd been discovered while refusing to talk about it. And that was an outcome he did not want.

So he hadn't sent that message. Instead, he'd fired off a quick reply wishing her a happy birthday eve and saying he had to call it a night because he had an early start the next day.

He had no idea if he'd made the right choice to hold off on telling her. In fact, he still didn't know whether he'd tell her or not. He was stalling for time.

Around 1am, he found himself wondering if it was possible she might even be happy to find out he was Derrick. She had named herself after the character he'd based on her – maybe that meant something. Maybe it meant there was a chance she had feelings for him, whether or not she'd admitted it to herself yet.

And this thought led to him imagining (not for the first time) a world where he and Beckett could re-enact some of the scenes he'd written for Nikki Heat. A world where he cold finally get through some of those walls she kept so strongly around her.

At some point he fell into a restless sleep and when he woke up in the morning, he still had no idea whether telling her would push her away or draw her closer.

Kate's plan to treat her birthday like any other day was thwarted repeatedly before her morning had even really began.

Walking towards her desk, she passed Esposito who gave her a quick nod followed by a quiet 'happy birthday, Beckett'. Subtle, brief – she decided she could deal with that acknowledgment of her birthday.

Sitting down, she was distracted almost immediately by the glimmer of something hanging off her computer.

'What the,' she muttered, leaning closer to study it before realising it was an ornament of a four leaf clover. A frown creased her forehead as she tried to figure out who would leave this for her. It didn't exactly scream Castle but the man could be so unpredictable that she had almost come to accept the fact that you never really knew what he was going to do next.

'Happy birthday, Beckett!'

Kate jumped as a chirpy Ryan appeared next to her desk, his greeting significantly louder than Esposito's had been.

'Sssh! People might hear you!'

Ryan shrugged and sat down in the seat normally reserved for Castle.

'So what do you think of the four leaf clover?'

'It's… Wait – wait a minute, that's from you?'

'Yep,' he said proudly. 'It's a good luck charm.'

'Thanks,' she said before the frown quickly reappeared on her forehead. 'You think I need a good luck charm?'

'Um…' Ryan grappled desperately for a few moments, trying to think of the right thing to say, but was spared by a loud exclamation of 'Kate!' followed by Lanie tearing towards Kate to give her a hug.

'Happy birthday!'

Kate tried to escape from Lanie's grasp, not noticing Ryan taking advantage of the moment to make a quick exit.

'So,' Lanie said, finally releasing Kate and sitting down where Ryan had just left, 'what are your plans for the big day?'

'Lanie, you know I'm not –'

'Really a birthday person,' Lanie finished for her. 'I know, I know – but you've got to do something when it falls on a Friday.'

'I'll have dinner with my dad if I can leave work on time.'

'And then?'

'And then, I'll go home.'

'That's it?'

'That's it.'

'No date? Not even a drink?'

Kate shook her head.

'Come on, it's been almost a week since you downloaded that app.'

'Lanie, shush!' Kate exclaimed, looking around her. Why was she having to shush people so much more than normal on her birthday of all days?

'What about sunset guy?' Lanie whispered, leaning closer to her.

'We're just…talking,' Kate whispered back.

'Incoming,' Lanie said, standing up and looking behind Kate. 'But you and I are having drinks tomorrow night, okay?'

Before she had the chance to protest or agree, Lanie had walked away and a cup of coffee was placed in front of her.

'Happy birthday, Beckett,' Rick said as he sat down.

'Thanks,' she said cautiously, picking up her coffee and figuring she needed it to get through whatever birthday celebration Rick had up his sleeve.

'Am I looking especially handsome today or something?'

'What?' Kate asked in confusion.

'You're staring at me.'

'No I'm not.' She quickly moved her gaze to her coffee cup instead and it was then she noticed that one side of it had been covered with drawings of balloons and a cake.

'You said you didn't like cake but I figured maybe a picture of a it on a coffee cup would be okay.'

Kate's lips turned up in a smile.

'Hey!' Rick exclaimed, looking over at her computer. 'Cute four leaf clover.'

To Kate's surprise, the rest of the day passed normally. There were no more good luck charms or illustrated coffee cups. She was even able to leave work on time for dinner with her father.

She couldn't help but admit that she was surprised Castle had restrained himself to just drawing on her coffee cup. The whole day, a part of her had expected (and feared, in equal measure) a flash mob to appear singing her some birthday song he'd written just for her. Or something just as public and humiliating.

She wasn't disappointed, she told herself as she walked back into her building after dinner. Definitely not.

Kate stopped in her tracks. There was a box outside her front door, covered in wrapping paper that garishly declared 'Happy Birthday!' over and over again in different colours.

There was only one person she knew who would use wrapping paper like that.

She let herself into her apartment, placing the box on her kitchen table and staring at it.

Should she shake it first? Or just unwrap it?

'Get a grip, Beckett,' she muttered to herself, rolling her eyes and reaching for the card on top.

Happy birthday, Kate!

You thought you were just getting off with that coffee, didn't you? Well, you thought wrong.

Enjoy what's in the box and, most importantly, enjoy your birthday! If anyone deserves to, it's you.

Rick

P.S. I've seen you devour a cupcake before so don't pretend like you don't enjoy them. ;)

She slowly opened the gift: there were the cupcakes, carefully stored in a box within a box and with various delicate decorations on top. But there was also a bottle of champagne, a novel she'd listened to Rick raving about for the past month and a container of bubble bath.

With a smile, she took the bubble bath and the book, and headed to her bathroom.

It was only as she settled into the bath that she remembered the wink at the end of the card and Derrick's comment about there being no such thing as a friendly wink.

Rick had almost signed the card off as Derrick, thinking it would be the perfect time – and maybe the perfect way – to let Beckett know but he'd changed his mind at the last minute.

To be honest, there was a pretty high chance he'd changed his mind simply because he was scared of Beckett's reaction.

But, he tried to convince himself as he sprawled out on his couch, maybe this was for the best.

Maybe this was a good way to prepare Beckett for who Derrick was.

He could keep messaging her as Derrick, find out exactly what Beckett liked and then plan the perfect reveal accordingly.

The fact that he got to flirt with her without fear of physical violence didn't hurt, either.

Derrick: Happy birthday, Nikki! How has it been?

Nikki: Thank you! It's actually been a good one.

Derrick: Aren't people meant to have good birthdays?

Nikki: Very funny.

Derrick: So what made this one good?

Nikki: The usual things. Coffee. A busy day at work. Good food. Winding down with a book and bubble bath.

Derrick: Nikki…are you in the bath right now?

Nikki: Wouldn't you like to know. ;)

Rick was pretty sure he gave a small squeak. Was Beckett messaging him from a bubble bath…with the mix he gave her?

He felt like patting himself on the back for not telling her he was Derrick.

Derrick: So a book and bubble bath. All you need is wine to make that perfect.

Nikki: Nah. I had a glass at dinner with my dad so I'm set.

Derrick: A glass? As in singular? On your birthday?

Nikki: Yep.

Derrick: You disappoint me, Nikki.

Nikki: You amuse me, Derrick.

Derrick: Glad to be of service.

Rick looked at his door in confusion.

It was 8am on a Saturday. And somebody was knocking on it.

He gave a sigh and ambled over in his dressing gown, hoping that Alexis or his mother hadn't signed up for some at home personal training course that would make this a weekly occurrence.

His confusion grew when he saw who was on the other side but he opened the door quickly nonetheless.

Standing there, holding coffee and the box of cupcakes he'd sent her yesterday, was Beckett.

'Come in.'

She walked over to the kitchen bench to place the cupcakes and coffee down.

'I wanted to say thank you for the gifts you left. And I wanted to share the cupcakes with someone.'

'Please tell me you ate at least one of them.'

Kate cleared her throat and mumbled something that sounded suspiciously like 'three' while she busied herself with handing Rick his coffee.

'You didn't have to do this,' he said, sitting down as Kate followed next to him.

'Neither did you.'

'Anything goes on birthdays.'

Kate opened the remainder of the cupcakes and offered one to Rick.

'You didn't happen to bring the champagne, too, did you?' he asked, after a few bites of the cupcake.

'Castle, it's 8 in the morning!'

He shrugged. 'We could have had birthday mimosas.'

Kate rolled her eyes and focused on her cupcake and coffee.

'Thank you, though,' she said a few moments later. 'It was a really nice end to my birthday to come home and find that.'

'You're welcome.'

'Do you know why I don't really like my birthday?'

Rick shook his head, not wanting to interrupt on the rare occasion that Beckett told him something private.

'When I was a kid, I used to write a list every year before my birthday of what I wanted to achieve that coming year. And then on my birthday, I'd look back on the list I'd made the year before.'

Rick was momentarily distracted by a bit of icing that was still on Kate's lip but she quickly wiped it away.

'As I got older, it seemed like the things I hadn't achieved became bigger and bigger, and there was this gap between where I thought my life would have been and where it actually was. And I don't like to be reminded of that gap.'

She looked up at Rick briefly before looking back at her cupcake.

'But lately, I've been thinking that even though my life hasn't turned out exactly the way I thought it would, maybe that's not always such a bad thing.'

He hesitated for a moment, not wanting to say the wrong thing or take it a step too far.

'I don't know where you pictured your life being by this stage. But Kate, you're doing amazing things with your life. Anyone can see that.'

She flashed him one of her big smiles and in that moment – more than he ever had before – he knew that he was completely head over heels.

Will Castle get the courage to tell Beckett that he's Derrick? Or will the fun and games continue?

Review to find out!