Oliver lives with his father, who is a nasty man and unscrupulous lawyer. His sister, who has been raising Oliver since their mother's death, decides to leave their sea side town and move to London to live with an aunt and uncle. After the family home is destroyed in a flood and his father leaves without telling him, Oliver is sent to an orphanage. He does not appreciate the hard life there and decides to run away to join his sister in London. This does not go well-- he steals money from a shipwreck, but that is soon taken from him by bandits who force him to help them rob stage coaches. He falls in with a man named Hawkes who gets him involved with Jonathan Wild, a notorious criminal. He does eventually find his sister and father, but it is under less than helpful circumstances. All three of them are eventually sentenced to death for stealing, and only his father's bribes to the judge get the children's sentences commuted. Oliver is glad that he will be sent with his sister to America, but soon learns that they are to be separated. Will they be reunited in the second book in the series?
Oliver is a stalwart character who doesn't let criminals, hunger, evil relatives or even a death sentence stop his undaunted desire to better his lot. He is sympathetic to his father... to a point. He realizes that the man has had challenges, but eventually calls him to task for his bad parenting. I do like one phrase that is sort of the family motto-- "People care nothing for suffering. To get on, you must mask your heart with false smiles." Oliver has very much taken this to heart, and it serves him well.
Readers searching for authetic historical novels like Updale's Montmorency, Lee's A Spy in the House, or Bradbury's Wrapped, will do well to pick up The Unexpected Life of Oliver Cromwell Pitts or any number of Avi's own books that deal with this period of history.