Professional organizer Zoe Lemonopolous finds herself in her mid-thirties, well employed, married to a sensible and kind if dull dentist-and pregnant. She's agreed to have the baby but cannot imagine herself as a mother. Although her life has all the hallmarks of the successful adult existence she was sure she wanted, she senses her life spiralling out of control. Everything is further turned upside down when she reluctantly agrees to spend a week away from her carefully composed life in trendy downtown Calgary.

Zoe returns to rural Concord, her childhood home near the shores of Bitter Lake, to help pack her parents' belongings and move them into seniors' housing. There, she clashes terribly with her troubled younger sister, is shocked by the signs of her parents' aging, and has a passionate affair with an old high school crush, Kyle, who makes her wonder what might have been.

On the shores of Bitter Lake, Zoe must come to grips with the tragically bad decision that has haunted her family for decades so that she can put the past behind her and begin charting the course of her future.