Set in Putney, London on the night of Friday, 16 June 1995, the novel takes the form of an interior monologue by a 49-year-old mother addressed to her sleeping teenage children.
It takes her a few hours—from late at night until dawn—to collect her thoughts and rehearse what she and her husband, who is asleep next to her, are going to tell their son and daughter on the following morning, which for the latter will amount to a rewriting of the family history reaching back as far as 1944.
Mike, who remains an only child, develops an interest in nature quite early in life and eventually, in the 1960s, decides to read Biology at the recently opened University of Sussex.
That man, "Grandpa Dougie," born shortly after the turn of the century, contributes to the war effort by deciphering code somewhere in the English countryside.
Already during her years at school Paula feels her father's growing estrangement from his wife, a development which culminates in divorce and "Grandma Fiona" running off with a man her own age "dripping with some kind of oil-derived, Texan-Aberdonian wealth".
[...][1] Mike's diagnosed infertility prompts them to remain childless (rather than try to adopt children) and to stay together, Paula suppressing the biological urge to procreate and look for a different partner.
[2] The vet becomes Paula's confidant (and lover, but just for one night), and he advises her to reconsider her abandoned wish to have a child while pointing her to the options available to her through the fledgling field of reproductive medicine.
She also makes a mental note to explain to them that they should decide wisely whether to tell anybody the news or not as the implications would be far-reaching: Grandma Helen, for one, might feel cheated out of her grandchildren.
No loving mother would keep her almost grown-up children in the dark for 150 pages (the equivalent of several hours of continual talk full of foreboding) and only then divulge the real reason for their unusual meeting: "This would be a sadistic scenario if it was possible to take it seriously.
About the character of Paula, Shriver deplores that the "apologetic, alternatingly gushy and beseeching style seems artificially female—like a man's idea of a woman's voice.
"[4] In the same vein, Carol Birch, calling the book "a disappointment," notes that Tomorrow "hangs on the device of a secret about to be disclosed, blazed before us from the outset as potentially life-shattering, and trailed like a banner.
"[5] Birch claims that teenage children would wince at the kind of confession Paula is about to make: "It's toe-curling, too, when she regales them with how wonderful sex is for her and their dad.
"[5] Only Anne Enright goes a step further and says that, once the secret is out of the bag, "we are free to stop guessing and start enjoying the novel's more delicate truths" as the book "weaves and undoes its quiet magic, making and scattering different kinds of 'family' [...] This is part of Swift's overwhelming honesty as a writer: he writes the way that life goes.