Earl, Cheri Pray

Twins George and Gracie travel back in time to Hershey, Pennsylvania where they become involved in a dangerous game of intrigue when spies try to steal the secret chocolate recipe from Milton Hershey.

Twins George and Gracie travel back in a time machine to Delaware during the Revolutionary War to rescue their stranded parents and in the process help Caesar Rodney cast Delaware's crucial vote for independence.

"During the coldest winter ever, George and Gracie land in Menlo Park, New Jersey, 1879--near Thomas Edison's famous laboratory. Mr. Edison has just invented a long-burning light bulb, but he's keeping a huge secret: he's also discovered time travel. The twins need Mr. Edison's help to protect the time machine from Crow. But will they stop Crowe in time?"--Back cover.