The full title of the book is The History of Tom Jones, a Foundling, and to some extent the plot is built round the question of the hero’s identity.
The story consist of three main parts. The first begins with the discovery of an infant – Tom – in the bed of Squire Allworthy, a rich and benevolent gentlemen who lives in Somerset. Tom’s origin is mysterious, but Mr Allworthy takes pity on him and brings him up with his own nephew, Blifil, who constantly seeks to harm the generous, open-hearted Tom. The two boys receive the same education, but while Blifil remains a mean and odious hypocrite, Tom grows into a brave, manly and likeable young man, sometimes impulsive and too pasionate, whose impetuousness often leads him into trouble.
He falls in love with Sophia Western, daugther of a neighbouring squire, but he is socially inferior and so a marriage between them is impossibile. Moreover, the jealous Blifil’s machinations against him lead to Tom’s banishment from Mr Allworthy house.
The third and last part set in London, where Tom has established, and where Sophia flees to avoid a marriage to Blifil. The major characters are brought together and, through revelation and recognition, they achieve the dénouement. Betrayal and macchinations are unmasked, and it turns out that Tom is the illegitimate child of Bilfil’s own mother – Mr Allworthy’s sister.
He is thus recognised as Mr Allworthy’s heir, and his marriage to Sophia meets with no opposition.