Everything is perfect in Cate's world.  She has the house of her dreams.  She's married to Gerald, a hard-working, if reserved man.  She has good friends and book clubs and baking circles.  She's happy.   And to top it all off, today is her birthday.  

But, when her younger sister Maggie shows up, uninvited, and gives her a bizarre birthday present, Cate's carefully crafted world begins to fall apart.