"Oh I have sown my love so wide
That he will find it everywhere;
It will awake him in the night,
It will enfold him in the air"
- Sara Teasdale

October 28:

They did it every single year. But it never ceased to make him feel loved. Spencer blew out the 38 candles on his cake.
"Happy Birthday to you...", Penelope sang the loudest.
He sat there among his friends, wishing his mother and Monica could have been there too.
"Here's your cake, birthday boy", JJ handed it to him.
He thanked her and the rest of them. They must have sensed he wasn't really in a celebratory mood. No one insisted that he stay. It was almost 1:00 AM anyway. Reid thanked them again and took his leave.

After he got home, there was a note and a present waiting on his night stand. The handwriting made him smile before he could even read the words.

'This isn't a sweet gesture. It's selfish. I want to be the last thing on your mind before you go to sleep. Happy Birthday'

'You always are', he thought and took the present.
Sitting down on his bed, he unwrapped it. Knowing Monica, he had expected it to be a book. But these were two tickets. A flight ticket to Belgrade, Serbia, in his name, and a museum ticket to...
His heart almost stopped.
The Nikola Tesla Museum.
Folded between the tickets was another note:

'You can forget about sleeping. Jennifer's confirmed your three-day leave with Emily. Call me when you get this. Your flight leaves at 4:00 AM. xoxo'

He wasted no time in calling her. As expected, she had been waiting for the call.
"Monica, how could you afford this?" - was his first question.
"I arranged for it months ago. The ticket was cheap. And the museum ticket was a favour returned by one of my colleagues"
"But..."
"Just say 'thank you', Dr. Reid. Or don't. At least tell me if you liked it"
His voice was mellow.
"You're not coming with me?"
"Sorry about that. I got a work thing"
The woman was transparent, even on the phone.
"You're lying"
"I'm so not! I just have this-this family thing I gotta be there for!"
"You just said it was a work thing"
"I... are you calling me a liar, Fed?"
He smiled,
"I'm just saying I can see right through you"
"Oh yeah? I can see through you too. I can even tell exactly what you're doing right now. That's how well I know you"
"Give it your best shot"
"You're cradling the phone to your ear, 'cause you're taking off your shoes or tie or something. The left corner of your mouth is slightly raised because you're trying not to laugh, but I'm hilarious"
He laughed,
"You're good"
"Really? I got that right?"
"Yeah"
"Woohoo!"
"Monica", he tried it another way, "It's my birthday. Won't you come with me? You can pay me back for the ticket later if you want"
"Uh-uh. I am not taking sex and money from you. Which reminds me, we're going to, double quotes, celebrate your birthday when you get back. I have something really special planned"
He touched a hand to his face, blushing. Monica said,
"All right. Enough foreplay. Please start packing. You will not miss this. Those tickets were a once-in-a-lifetime score for me. This whole week, all of Tesla's personal effects they have - including his handwritten notes - are going to be on display! It's going to be like a Tesla fiesta. You've gotta go!"
Overwhelmed as he was, he managed to speak.
"I don't know what to say"
He could hear the smile in her voice.
"There's something I have been meaning to say, but I want to see your face when I say it"
"What is it?"
"Nothing that can't wait. Now start packing or I'll come over and make you"

November 9:

She had given him a birthday present he would remember all his life. And on her birthday, he was a thousand miles away, trying to catch a spree killer.
"Reid"
He looked up to find Luke standing by the desk.
"Do you need a ride to the hotel? Man, you look like hell", Luke said, "We'll come back to this tomorrow with fresh eyes. Come on"
Gathering his coat, he followed Luke out of the local police station.

It was 2:00 AM when he reached his hotel room. The first thing he did was call Monica. Part of him wished he should let her sleep, but he didn't know when he'd get the chance to call her tomorrow.
"This is Monica Knight and her imaginary friends. Leave a message!"
He sighed. She was asleep.
Beep.
"Monica, it's Spencer. Happy Birthday. I know I should be there with you today and not here but...", he said, "I just wanted to tell you I'm sorry I couldn't be there with you. I hope you have fun though. And... listen. There's something I... something I want to tell you. But I guess I better say it to your face. You probably already know it anyway. Well... happy birthday again. Good night"
Beep.