No love is as safe as that of an inseparable sister, no hurt as deep as when she leaves without a trace. St. Paul, MN, 1946: As little girls, the Malone sisters relied on each other for companionship and affection as their mother remained distant, beating back the demons of her own mysterious childhood. Now young women, the closely-knit sisters endure separate tragedies that threaten to tear them apart. Diagnosed with tuberculosis, Shannon undergoes a life-saving hysterectomy while Eliza suffers a shameful, unexplained pregnancy. Eliza delivers and relinquishes a baby girl, and quickly leaves home-perhaps forever-taking her secrets with her. Broken-hearted, Shannon vows to hold onto the invisible thread of sisterhood, certain it will eventually bring Eliza back.