Help me understand the plot of Aetherdrift. I have burning questions.

From what I understand, Chandra is trying to win a planeswalker spark for Nissa. Would it be fair to say that Chandra is churning, and burning, and yearning for the cup? Striving and driving and hugging the turns, and thinking of someone for whom she still burns?

And where is Nissa in all of this? Is she all alone? All alone in her time of need?

Thanks in advance