To be honest, after only reading Outlanderexclusively for 2014 (it will suck you in), all the books are starting to merge a bit. The 6th book in Diana's Gabaldon's Outlander series is A Breath of Snow & Ashes. A Breath of Snow & Ashes (ABSA) follows Book 5 pretty closely in that the Fraser/MacKenzie clan is still on The Ridge and Stephen Bonnet still has yet to be taken down!
ABSA focuses on the family finally being a family, and what that means when you all live together in the wilderness of North Carolina. She's setting the roots for what I think will guide the family for the rest of the series. Gabaldon is definitely plotting things throughout the book that may not have much significance in the 6th book specifically, but you know will be picked up later.
I think what I love so much about this series is that it's constantly telling these character's story. There are no years, or long stretches of time, that are just not mentioned - you're even still learning bits and pieces about the 20 years that go between Claire & Jamie. I also love how different all of the main characters are, and how Gabaldon's writing style changes vastly with it. You know within the first paragraph what POV you're reading, which is fantastic.