Outlander by Diana Gabaldon
Fity shades of tartan!
Claire is married to Frank Randall, and after eight years spent as a nurse during world war two, they decide to have a new honeymoon in Scotland, where Frank makes researches about his ancestor who lived in the 18th century.
Claire picks up plants and flowers, and one day, in a stone circle, she disappears from her world to appear in the 18th century!
She's saved from the assaults of Jonathan Randall, her husband's ancestor, who looks exactly like him, by a young scot, Jamie, and she's adopted by his family.
But no one understands who she is : is she a spy? As and English woman, is she spying for the King of England? Is she a witch, as her knowledge in medicine is far too good for a woman?
Jamie, has his share of problems, having been tortured by Randall and accused of a murder, he's an outlaw.
They get married so Claire can be a scot and they find they are in love...As we thought they would be!
And the situations are more and more complicated...