Talim sounds adorable and the kind of person that Ondorus would get along well with (and she's in Goldenrod too!), but damned if I can't think of a way for them to meet, unless you'll be doing a post re: the pokemon thing.

...when you say "go missing", do you mean actually disappear or that they'd get stolen and she'd know about it? Because Ondorus works at the Foster Home and that might seem like a place to check at if someone just loses a Pokemon.

alternately if she's freaking out in the pokecenter or something