Infinity Ring: #01 A Mutiny in Time

When best friends Dak Smyth and Sera Froste stumble upon the secret of time travel — a hand-held device known as the Infinity Ring — they're swept up in a centuries-long secret war for the fate of mankind. Recruited by the Hystorians, a secret society that dates back to Aristotle, the kids learn that history has gone disastrously off course.