Sixteen-year-old Kit Tyler has lived most of her life on the sunny island of Barbados, raised by her wealthy grandfather on his plantation. However, his death in 1687 forces her to go live with her only remaining relatives: her Aunt Rachel and Uncle Matthew in Wethersfield, Connecticut in the Connecticut Colony. Her grandfather's money was spent paying off debts and her only other option was to marry a man much older than her.
The atmosphere of the strict Puritan colony is very different from Kit's previous home, and she chafes under all the restrictions on her behavior. Lonely, she befriends elderly Hannah Tupper, a Quaker who was expelled from the Massachusetts colony because of her religion and a suspicion that she is a witch. Through her friendship with Hannah, Kit develops a relationship with Nat, the son of the captain that owned the boat she arrived on. She also befriends a young girl named Prudence, whose abusive mother refuses to let her attend school.
For a chapter by chapter summary (a rather tall order) you'll have to look at the links or read the book. The above is as much of a summary as I can give in 1500 words.