The Reluctant Traveler - The Travelers' Chronicles, #1

Meredith's beloved brother has died, and his troubled, teenage daughter Kimberly blames herself for his death. Meredith tries to comfort her niece but instead witnesses Kimberly disappearing into thin air. Leaping after her, the pair find themselves in an unknown, medieval-like land. Was this the home of Meredith's three exotic childhood friends she'd met all those years ago? The ten-year old Meredith had believed their tales, but the adult Meredith, who'd chosen a practical career over pursuing her art, had dismissed silly fantasies years ago.
Feeling stranded and powerless, they begin searching for Meredith's old friends but instead find danger. Fleeing, they become separated. Meredith eventually reunites with Lox-a man even more charismatic and intriguing than the boy she remembered-but the pleasure of their reunion soon evaporates in a cloud of confusion and betrayal. There is trouble in this land-trouble Meredith seems to hold a key to solving.
But who can she trust? And where is Kimberly? Will she ever find her niece and get them back to their own world? Even if she succeeds, Meredith knows her life will never be the same.