The malignant cells now number in the tens of millions. Having successfully migrated from the breast, they prosper in new environments; even when completely autonomous, free of all contact with their fellows. They have proven particularly adept at infiltrating bone.

She tries hard to ignore the nagging pain. It is one more demand on her patience in a life full of such demands. For years she’s been saying she doesn’t believe in illness. Anyway, the Tylenol in her desk drawer still provides the temporary relief she needs.

The progression is relentless. A malignant cell observes none of the constraints that inhibit normal ones. Each is now the equivalent of a professional killer, plundering nutrients that normal cells need to survive, showing contempt for physiological equilibrium and tissue architecture. The tumor replicates itself every three weeks. Each new generation of malignant cells is even more aggressive.

Her husband knows her better than anyone. Before bed one evening he notices—not for the first time—that she is vigorously massaging the small of her back. Shrugging off her assurance, he insists she have it looked at.