None of them had ever heard this story before, so they were all captivated by Isaac's story and so Isaac told them: "The King of the Drakonits is still the same as the one back then, so yes, I know them very well, and once we tell them the situation, their is no doubt that they will come to join us in this war, you'll see."
Isaac then answered a few of their questions and when their curiosity was satisfied, since in any case Kevin and Axel couldn't leave before Atlas returned and stabilised the huge quantity of black particles he was absorbing, they decided to go and join their daughter who must have been impatiently waiting for them.
But when they teleported to their personal dimension where they had left Willow, she was no longer there...