The Time Cavern(2008)
(The first book in the Aaron and Jake Time Travel Adventures series)
A novel by Todd Fonseca
When ten-year-old Aaron moved from the big city to the middle of Amish country, he felt transported to a different and simpler time and place. But after finding a faded and long forgotten diary page of a boy gone missing over one hundred years earlier, Aaron began an adventure more wondrous and exciting than he could have ever imagined. Befriended by a local farm girl named Jake, together they search for answers to this century long mystery and uncover the secrets of an astounding cavern that will take them to the edge of time itself.
Used availability for Todd Fonseca's The Time Cavern
June 2008 : USA Paperback