It was impossible to track time within CAL's computer system, but River Song attempted to do it anyways. She was the sort of woman who'd always be up for a challenge, and she decided to keep tabs how much time had passed. 

Today, it was supposed to be Valentine's Day, at least according to what she had jotted down on a piece of paper. She remembered her life before the computer and how he used to take her out for dates. The Valentine's Day ones had always been the most romantic, the sweetest. She had adored every moment of it.

No matter how wistful it made River feel, she couldn't allow herself to dwell on it. There were children to be cared for. She couldn't let a silly little Earth holiday get in the way of her daily duties. Making her way downstairs, she found Brook already playing with the children.

"Hello," Brook said. "You look sad, very sad...is there something wrong?"

"No, no," River replied, faking a smile in order to reassure her daughter. "Nothing's wrong. I just wanted to say that today's Valentine's Day. At least, I think it's supposed to be."

Brook took several moments to respond as she attempted to wrangle up the two younger children. While Charlotte Abigail Lux was calm and collected now that she had been fixed, the computer generated children acted their age - and that meant they would run around like mad.

"Valentine's Day?" Brook echoed. "Well, now I know what I can have Christine and Ian do today," she said, glancing down adoringly at the two children she now had wrapped up in her arms. "They can make some Valentines for everyone here!"

River nodded her head absentmindedly, finding her mind drifting away again. She was lucky to have her daughter there in order to help out with the children. There were three to keep track of, all of them requiring full attention even if they weren't technically real children. 

"Come on, let's go make some Valentines!" Brook called out cheerfully, attempting to round up the children. "Just go down the hall and I'll be right there in a moment." She urged Charlotte, Christine, and Ian onwards with a flick of her hands. Once they had walked away, she turned to her mother.

"Happy Valentine's Day, Mum," Brook said, throwing her arms around River's neck. "I love you."

"Thank you," River replied, wrapping her own arms around Brook's waist. "I love you too, sweetie."

Brook then backed away from her mother and tucked a piece of her dark hair behind her ear. "I know you're thinking about Daddy. I just didn't want to bring it up in front of the little ones."

"No, I understand," River said. "I am thinking about him."

"Well, he does love you," Brook said, swallowing deeply. "I'm sure of that much. Even if he's never said in those exact words, I'm sure of it."

"He's never told me in those exact words - don't you see, Brook? That's what my problem is. Now I'm stuck in this computer for the rest of my life, never to see him again, never to speak to him again..." River's voice trailed off as she realised that Brook was beginning to tear up.

"Oh, Brook, sorry," she said, shaking out her curls in shame. "I didn't mean to say that. I know you're going through the same thing."

"No, no, it's fine," Brook sighed. "Foreman told me that he loved me plenty of times. You have a valid complaint."

River nodded several times, Brook's words just barely getting to her. The mother and daughter stood together in silence. 

"What's this?" Brook suddenly said, shutting her eyes tight. "There's something that's just popped outside...I don't understand...the data isn't computing in my head."

River made a start towards her daughter, reaching out to put a hand on her shoulder. Brook had access to the data core in her head, which made some things very easy for her to figure out. This had caused its fair share of problems as well, but at the moment it was an asset.

"We should go check it out," Brook said. "I'm sure the children will be fine. All they have is paper and crayons. No glitter, glue, or scissors."

"Then we might as well," River replied, nodding slightly. They headed to the front door and made their way out, looking over the vast expanse of green that made up the house's lawn. Neither one had any clue what they were looking for, just that they were looking for something.

"Wait, what's this?" Brook called out as she leaned over and plucked a small piece of paper off the ground. River jogged over to her side to look at it. In her daughter's hands was a card made out of a deep purplish red paper.

"Amaranthine," Brook breathed. 

"What?"

"It's the color," Brook replied. "Well, amaranthine actually has two definitions. One: a deep purple-red. Two: undying, immortal, undyingly beautiful. Wait a moment...it has your name on it, written in Gallifreyan. River Song."

River didn't waste a moment of time, immediately plucking it out of her daughter's hands. Sure enough, her name was handwritten in the circles and lines of Gallifrey. Her hearts now pounding, she unfolded the card and looked within.

Dear River,

Sorry that this card is the only thing I can get into the computer. It's all very complicated, and you know better than anyone that I can just barely grasp the TARDIS's controls. But never mind all of that. I'm guessing that Brook has already mentioned something about amaranthine, how it has multiple meanings.

I did mean to do that, you know. It's sort of representative of things...you know? You're clever - I'm just going to assume you understand it. There's not enough room for me to explain and it and say what I have to say. 

Happy Valentine's Day, River!

-The Doctor

P.S. I love you, River. No matter what. It's undying...amaranthine. You see? Yes. I love you.