Mae Phil a George, dau frawd, yn cwbl wahanol. Er hyn, maent yn rhedeg busnes gyda’i gilydd ac yn cysgu yn yr un gwely roeddynt wedi fel plant. Ond, pan mae George yn priodi, mae Phil yn penderfynu dechrau ymgyrch i chwalu perthynas y ddau…

Phil is tall and angular; George is stocky and silent. Phil is a brilliant chess player, a voracious reader, an eloquent storyteller; George learns slowly, and devotes himself to the business. They sleep in the room they shared as boys, and so it has been for forty years.

When George unexpectedly marries a young widow and brings her to live at the ranch, Phil begins a relentless campaign to destroy his brother’s new wife. But he reckons without an unlikely protector. From its visceral first paragraph to its devastating twist of an ending, The Power of the Dog will hold you in its grip.