Two rival English football supporters of different classes fall for each other and discover that their ultra-competitive relationship might not survive the football season or their families.

Going to change a word:

Two rival English football fanatics fall for each other but must overcome their ultra-competitive natures if their romance is to last the season.?

"Two rival English football fanatics fall for each other but must overcome their ultra-competitive relationship if their romance is to last the season."

Do they have to be of different classes? That's been done a lot. The unique thing is the footballer rivalry, and the subtle threat that perhaps the other family members would get violent, as though Romeo's family would try to hurt Juliet.