They have something vital to discuss, Momo says. Everyone better show up or else, Momo says. Everyone except Mary that is, because when Momo strides into the room with purpose in her step, she's the only one missing. Kano's sprawled on the couch, though Seto's taking up one of the couch cushions and doesn't seem to mind the other boy's feet across his lap. Kido leans over the back of the couch, and the three pause, mid-conversation.

Shintaro is slumped in the corner like he's given up on life, so Momo decides to begin her speech by kicking him in the shins.

"Ow!"

She steamrollers right over his complaints. "Mary and I were talking about zodiacs, and she said she was a Cancer, and I said 'that's soon isn't it?' and she said her birthday's on the 21st." She pauses, waiting for the applause for her detective work. Shintaro looks confused, and the other three seem just as baffled.

"That's next week!" Momo cries, indignant. How could they forget something so important? "We've gotta throw her a party or something."

The others finally get it. Kido's eyebrows shoot up, Seto looks away, and Kano curls up on his back in a poor attempt to contain his laughter.

"Oh man! Momo-chan really is determined about this, I hate to break it to her…"

Momo feels like they're sharing some kind of joke at her expense. Did they already have a party for Mary? Was she not invited?

Kano's still laughing, and not explaining any further, so Momo demands answers from the others. "What is he talking about?"

There's some shuffling. Kido straightens up and stretches a kink from her back, and Seto scrubs a palm against the back of his neck, finally explaining gently, "Mary really hates birthdays. We try not to make a big deal out of them."

Momo is unconvinced. How could anyone hate birthdays? But through peals of laughter Kano explains, tells the story of preparing for Seto's party just a few months ago. How she'd seemed fine enough, excited even, but when they'd been decorating the cake…

"She's in the middle of writing on it, right?" Kano writes in midair with his pointer finger, continuing, "and right in the middle of putting Seto's age on it, we notice she's crying. Right on the cake!"

Kido's had enough of his story and seizes his pointer finger, bending it backwards as his yells of 'OW' begin to increase in volume. Seto finishes the tale.

"Anyway, we just don't like to bring it up. She's gonna be 142 this year, so maybe she's lost interest in birthdays by now?" He doesn't sound half convinced though, and it's enough of a weakness for Momo to make her case. And she makes it brilliantly.

…

One week later, and they're decorating the base. They've been at it for an hour or more, and the paper chains and streamers are finally starting to look festive instead of pathetic. There are brightly wrapped packages on the table, color-coordinated too; Momo adds her rectangular orange one, smiling a little. It's a doujin anthology Mary mentioned once, disguised with a book-jacket from a book on fairy tales. Momo thinks she's rather clever.

Kido and Shintaro are helping her decorate. The other two are distractions for Mary. Seto, because she trusts him more than any of the others, and Kano, mostly because Seto— Momo winces as his voice booms from just outside the door, "MARY, ISN'T IT NICE TO BE BACK AT THE BASE? IT SURE IS NICE. I THINK IT'S NICE."— is a shitty-ass actor.

Momo finishes tying off the balloon she was blowing up and motions to the others to get behind the couch. She joins them, just in time too as the door swings open. She gulps in a breath of air, then flings herself to her feet.

"SURPRISE!"

Thank god, no one missed the cue, every single one of them shouted in unison, and Kano set off the party poppers he'd up until then concealed in his hands.
Everything goes quiet.

Momo is suddenly afraid. What if the others are right? Mary is just standing there like a statue (an idea that almost makes Momo laugh through her terror), her eyes wide as she takes in the scene. Momo sees Kano's expression waver and re-affirm into a solid grin, whatever face he was going to make buried beneath his ability. She sees Seto's mood do a solid 180 and he moves closer to the tiny girl, presumably to do damage control.

But that's when it hits Mary. She squeals and throws her arms around his neck, then spins and hugs Kano too. Momo hadn't noticed herself crossing the room, but suddenly Mary's right there and hugging her too, and there are little spots of wetness on her pink hoodie that could be tears maybe, but maybe not.

"Thank you so much, everyone!" she exclaims, beaming and practically glowing with happiness.

Momo knows they made the right choice. Instead of 'Happy birthday', or any mention of her age, every cake and banner says in bright letters, "We love you, Mary!" It's something, she reasons, that everyone needs to be reminded ever now and then, immortal or not.