The point where the plot resolves itself is when the Sealand people find out that David and his friends are in trouble and decide to come help.
David and company have had to escape and are stranded with a pack of rabid Fringers led by David’s uncle descending on them. David’s spidery uncle blames him for his ousting.
Things are looking bad, but Petra believes help is on the way.
'The Sealand people are coming to help. They're not so far away as they were, now,' she told us confidently. (ch 14)
Still, things are not all rosy. Help does not come right away. David’s father’s older brother wants to leave them where his father will find them. The Sealanders have not come to help yet. One of the men is advancing on Rosalind, and David tries to fight them off. They beat him and leave him in the bushes. Things look dire, because their pursers do find them and are closing in—but at that point the Sealanders do come and rescue the telepaths.