The Voice From the Well - The Velessar Saga, #1

Stranded in a foreign world, Jay must fight to reclaim his stolen memories as mysterious forces conspire!Soon-to-be seventh grader, Jay was on a nature walk with his family. The next moment he's tumbling through a dark void, landing in an overcast forest completely alone. Taking shelter for the night in an old lighthouse, Jay encounters something in the deep darkness that hovers in the corner of the room.
The following day, Jay wakes to find he can only remember small fragments of the day before. Everything about the lighthouse and the small nearby village is wholly different than the few things he can remember, almost as if he'd stepped back in time. When Jay encounters a strange whispery voice that offers him help at a price, he begins an adventure fraught with peril.