Can be established Spirk or they could realize their feelings in the fic, but I want to see a Spock that believes that Jim Kirk loves the Enterprise the most and would give up captaincy for absolutely nothing. Cue disaster in which Kirk proves everyone wrong, preferably by taking the fall for the rest of the crew and resigning his commission.
Bonus points if Bones is the one who has to explain to Spock that Jim loves him. (Maybe the phrase: Dammit! I’m a doctor, not a matchmaker! God knows why he would, but Jim loves you, you green pointy eared bastard.
It’s also preferable that Jim gets his commission back at the end because Spock and his crew stepped up in his defense.