Quite a nice idea.
I'd originally have thought that the King wouldn't send Dhruv for this mission (he's not a soldier after all), but you could say that Sukku has to go (to potentially identify her father) and she wouldn't go without Dhruv.
Maybe even have Sukku as D-T's pretend daughter for a bit in the other kingdom.
The idea of Sukku being D's daughter is something that's appealed to me, especially when he calls her "Chhoti Rajkumari". She's also the only person that has really trusted him throughout, and you often get those type of bonds only by blood. Unfortunately, logic says she cannot be D-T's daughter.
Writers, ab bhi kaun sa logic de rahe h . Inka stress bhara logic dekhne se achcha ye ek illogical, par cute sa magic hi dikha de