Okay, I've not read the novel, but i have seen a movie on that book and i hope the story is not different..
the parents would not allow both to marry so they would elope one day and would live a happily married life.
SOME YEARS LATER...
their parents would forgive each other (the girl's side would forgive the boy's one and same with the boy's side)
so both the parents would search for their kids.. and at last they find them but instead of screaming on them, they get surprised to see their grandchildren. then both the families live together not either in punjab nor in tamil nadu(or whatever the place is...) but in mumbai...
hufff... so here we come to an end to the story
enjoyed writing for you bye! (I HOPE THAT I GET THE POINTS)