In a huge old school house by the sea, full of precious paintings, Thomas Porteous is dying. His much younger wife Di holds him and mourns. She knows that soon, despite her being his sole inheritor, Thomas's relatives will descend on the collection that was the passion of both of their lives. And descend they do. The two needy daughters, who were poisoned against their father by their defecting mother, are now poison themselves. The family regard Thomas's wealth as theirs by right, with the exception of young Patrick, who adored his grandfather and is torn between his parents and Di, the interloper. The family know Di's weaknesses, and she has to learn theirs. After all, she met Thomas when she came to his house to rob him. With the help of an unlikely collection of loners and eccentrics, she sets a trap to hoist the family members on their own greed. And on the night they are lured to the house, Di will be ready. Or will she?