Kayabeth romance catalyzed by Accidental Baby Acquisition (in a manner similar to how I've seen it in a lot of Buddie 911 fanfics and no I'm not doing the parallels between them on purpose all the time) as yeah I know if Kaya was living with Elsbeth again it'd be an apartment and it'd be hard to easily discreetly do the baby-on-the-doorstep cliche in an apartment building but just like fire stations aren't police stations also places one can safe-haven unwanted babies so maybe a while after the dream team are back together they come back from a crime scene to a very noisy dropped-off-baby that [whichever of the two it'd be most in-character for as it wouldn't necessarily have to be Elsbeth just because she's had a kid before] seems to be the only one who can calm down and (if you'll pardon a turn of phrase they might use as a transition card if this was an episode) One Improvised Carrier Later the baby kinda ends up tagging along the rest of the day's investigation as they like them (and might not react the same way to even other women in the precinct) and while she (yes I feel like it'd be best for this prompt if the baby was a girl) proves helpful for getting people to let down their guard in interrogations she also causes witness and suspect alike to make certain assumptions about the two ladies. And then at the end of the day whichever of the two was the one that bonded with the baby asks her roommate if they could take the baby home and gets a somewhat nervous yes cue One Baby Shopping Trip Later as they've got nothing to deal with a baby without more improv.

And thus commences a B-plot-arc-y-thing of Kayabeth trying to balance their jobs with co-parenting this little baby girl with trying to figure out why her mother left her at the station and, if she's truly unwanted, what happens to her now like can they find someplace that could give her better than what they could or do they get to keep her (and if it wasn't one of those scenarios where the child was dropped off with a note explaining things like their name like you see in some fiction and Kayabeth got to keep-enough-to-name this little girl I imagine the name would truly be something special potentially (between first and middle) pulling from everything from departed family members of theirs (like Elsbeth's grandmother the way she talks about her) to pop culture hyperfixations of theirs to someone from Elsbeth's past iykwim) and in the trope-ily likely event they got to keep her might being mom-and-mom awaken some things within them that it seems everyone else sees before them (even before the daughter entered the mix) and Elsbeth get a second shot at having some sort of family

In this case it's no matter how much I'd want a crossover between Doctor Who and Elsbeth (if it could cross over with an American show I feel like these two would match each other's "freak (affectionate)" especially with Elsbeth's theatricality and magical realism and the fantasy elements and music motif of Gatwa's run-so-far) where Elsbeth's, like, at-least-part-Time-Lord or something (even if it has to be in a similar way to River Song), but in a way that'd still let her be her own person/not mean her world somehow don't real (said as people on the Elsbeth sub were speculating about how she might be some kind of split-off/lost-in-a-way-she-could-meet-others-without-weird-time-shit Doctor regeneration a la what happened with the Fugitive Doctor but that just unnerved the crap out of me, if she could be some kind of Time Lady she needs to be her own Time Lady), even if said crossover was canon Elsbeth having an imaginary friend named Belinda as a child doesn't necessarily automatically have to be an allusion to Belinda Chandra.