I'm wondering if there's a specific trope that covers something that SVU provides two specific examples of. . . .
1. There was that season where Detective Chester Lake was transfered into the squad and, for whatever reason, partnered up with Fin, even though Munch was still on the show at that point. Anyway, Fin and Lake barely had any chemistry whatsoever, yet by the end of the season with Lake's final episode where he goes rogue and becomes a dirty cop, then all of the sudden Fin is all concerned about his welfare and emphasizes that he's his partner, despite others telling him that he never made any effort to get to know him as a partner - even Lake himself tells Fin this when Fin acts like he knows what kind of person he is, and what he would or wouldn't do.
2. Detective Cassidy was part of the squad for only half of the first season, and was Munch's original partner before Fin . . . then several, several seasons later, Cassidy returns to the show in another unit, and for whatever reason, he and Olivia Benson end up becoming romantically involved with each other, despite neither of them showing anything of the sort for one another prior to his return.
So, what I guess I'm getting at is, is there a trope for when there are two certain characters that basically have no use for each other, but then all of the sudden, it's as if they were tight with each other all along despite their lack of interaction or involvement?