On a bitter-cold day, in the December of his junior year at Harvard, Sam Masur exits a subway car and sees, amid the hordes of people waiting on the platform, Sadie Green. He calls her name. For a moment, she pretends she hasn't heard him, but then, she turns, and a game begins: a legendary collaboration that will launch them to stardom. Sam and Sadie are college friends, often in love, but never lovers, and become creative partners in a dazzling and intricately imagined world of video game design, where success brings them fame, joy, tragedy, duplicity. and ultimately, a kind of immortality. It is a love story, but not one you have read before.