SPOILER!!! Regarding Jennet's … unplanned trip at the end of Fire/Sky

Elaine had an interesting question:

I think there are always memory gaps when you read a long series like this and I really appreciated the character lists at the front of each book. My "gap" involves why Jennet was abducted and why she was blackmailed. What were the big family secrets her abductor threatened to reveal?

The answer to this question was set up primarily in Dawn on a Distant Shore, which took place (in part) in Scotland. During this period Roman Catholics were discriminated against to an extreme that included the exclusion from landownership. The Carrycks were clandestine Roman Catholics. The repercussions would have been catastrophic for them, had Degre carried out his threat. Or at least, that's my take on it. Readers may disagree.