Sadie and Sam first meet as youngsters in a hospital gaming room. She is visiting her sister; he is recovering from a devastating car accident. They bond over their love of video games, but a misunderstanding leads to them falling out with a resolve to never see each other again.
Years later, Sam spots Sadie across a busy train station, and their connection is instant. From then on, they're inseparable (well, apart from all the times they fall out again). Together they begin to write games - not violent shooting games, but ones which give the player the escape from the real world that they'd both needed when younger. Their first game is a runaway success. But after that Sadie and Sam need to face the real world, which is never as fulfilling as a good game in which one may fail innumerable times but it's always possible to start over.
Tomorrow, and Tomorrow, and Tomorrow is a story of love, friendship, possibilities, misunderstandings, and, of course, creating games. I found it enthralling. Their relationship echoes a game. The periods when they don't talk to each other been the equivalent of a game-character's death. Their getting back together, the 'return to last saved level' and recommencement of the game. In games, though, it's possible to press restart an infinite number of times; life isn't so convenient.
It's an intimate and nuanced depiction of a long-term friendship - one where the friends are as close and inseparable as lovers. The characters are fully developed, flesh and blood people, faults and all. Their arguments and misunderstandings explored from both sides.
I'm not a committed gamer, though I'm fond of Lara Croft and some of the Lego games, and it took this book to show me that games are really in essence another form of story-telling - a small child is lost at sea and must find its way home, an older child is in hospital undergoing treatment but at the same time slips into a fantasy world where there are different obstacles to overcome - and stories are ways of making sense of life.