Mary is struggling with her memory. She does not have too few recollections but too many, including some that are downright absurd.

She has many memories of her childhood: going to parties and on school trips, walks with her father and family dinners. She remembers world events too: the falling of the Twin Towers and the Iraq War. But the most concerning memories she has are about her Jewish grandfather and his role in the death of Adolf Hitler.

She feels sure - almost completely sure - that what she has been told can't be true, that she must have imagined the whole thing. But there is a doubt.

To decipher fact from fiction, Mary goes back over her life, sorting through her childhood and adolescence with her three friends in York, through an adulthood accustomed to tragedy. Guided by her family and friends, Mary attempts to figure out what is real, both in history and her own life, all the while wondering if her mind has conjured everything.