Seventeen-year-old Lenni Pettersson lives on the Terminal Ward at the Glasgow Princess Royal Hospital. Though the teenager has been told she's dying, she still has plenty of living to do. Joining the hospital's arts and crafts class, she meets the magnificent Margot, an 83-year-old, purple-pajama-wearing, fruitcake-eating rebel, who transforms Lenni in ways she never imagined.
As their friendship blooms, a world of stories opens for these unlikely companions who, between them, have been alive for one hundred years. Though their days are dwindling, both are determined to leave their mark on the world. With the help of Lenni's doting palliative care nurse and Father Arthur, the hospital's patient chaplain, Lenni and Margot devise a plan to create one hundred paintings showcasing the stories of the century they have lived - stories of love and loss, of courage and kindness, of unexpected tenderness and pure joy. Though the end is near, life isn't quite done with these unforgettable women just yet.