Spoiler's for the previous book/Dark Sword series.
This is Ian's story. He was pulled into the future d/t his tie to Duncan (his twin who was murdered by Malcolm) and Dierdre. The individual responsible for pulling Dierdre to the future was Declan. Declan wants to rule with Dierdre, but she doesn't want to share. So, at this point they are not working together (so it appears). Ian hide because he didn't have control of his god; so he thought.
Danielle lost her parents were she was 12 and came to Scotland to live with her aunts, one of whom taught her about her magic. Danielle has the ability to return lost objects to their owners. She finds a key and must at once get to MacLeod castle. She finds Ian and together they find each other. Declan's main involvment in the story:
It remains to be seen just how her placement will play out. I maintain he is more of a threat then Dierdre. Dierdre's plant(show spoiler)
failed. Deirdre is still alive, but the artifacts are in place to locate Laria (who supposedly is the only one who can kill her).
Next up Saffron
From Dark Sword series: (There really needs to be a character list; I'm sure I'm missing someone)
Cara and Lucan, Larena and Fallon, Marcail and Quinn, Isla and Hayden, Reaghan and Galen, and Sonya and Broc. Marcail and Quinn's son, Aidan, then there's Ramsay, Camdyn, Arran, Charen, Phelan.
Dark Warriors: Logan and Gwynn