After The Star-Touched Queen -- different main characters but benefits from being read in order.
Vikram is trying to be taken seriously as his (adoptive) father's heir. Gauri is prisoner after her brother arranged it for fear she was growing too powerful. And Vikram meets with a sage who has a golden mongoose and a ruby with an invitation for him -- and one other -- to enter a Tournament of Wishes. It also tells him how to choose his partner.
When his father's advisors have him go to tell Gauri that she is to be executed -- her kingdom is pushing for it, and he knows they want it to backfire, so they can blame him -- he realizes that she is the one, and tells her so.
And the tale winds on. It involves disguises, women who are poison -- one of whom had had her husband's early death predicted when she was four, a riddle, a question whether a wife loved her husband or was carried off by him, a golden apple, and many more marvels.