Three young cousins are summoned by their evil Uncle Silas to spend the summer with him at Sommerset, his grand gothic estate perched on a mysterious island surrounded by an alligator-infested swamp. Silas Winterbottom, who has had virtually no contact with his extended family for decades (except to insult them or refuse their requests for money), is dying. It is his intention to select an heir from among his nieces and nephew - Isabella (13), Adele (12) and Milo (12). The Winterbottom children have very different backgrounds but each of them has a motive for accepting Silas' invitation. One of the Winterbottoms believes Uncle Silas is a murderer; two of them will do anything to win his favour and his fortune - and only one will be chosen.