Complex sentence: They make their way through the United States to Canada on the Underground Railroad with the help of Alexander Milton Ross, a Canadian abolitionist, eventually arriving safely, apart from Adam who dies of blood poisoning caused by his slave chains.
Split into simpler sentences: They make their way through the United States to Canada on the Underground Railroad with the help of Alexander Milton Ross, a Canadian abolitionist. They eventually arrive safely, except for Adam, who dies of blood poisoning caused by his slave chains.