Chip is a friend of Jonah from a book called "The Missing". Jonah is a 13 year old boy and both he and chip start receiving strange letters. Although Jonah already knew he was adopted, it turn out that chip was too. He received a total of 4 letters and ultimately the two went out to find the truth behind the whole problem.
They ultimately came to realize that they were smuggled from the 14th century into the 21st century along with 36 other children. The tale becomes treacherous as the janitor boy sends Chip, Jonah and his sister to the 14th century where they fight for a way to survive and come back to the 21st era.