She continued the ordinary business of a human life in the way that extraordinary events rarely disrupt permanently — they are integrated, eventually, into the texture of a life that continues.

The frozen night on Wally Nelson’s porch is part of that life.

It is the part that science has examined, that medicine has learned from, that journalists have written about and podcasters have retold and researchers have cited in papers on hypothermia management.

It is also, for Jean Hilliard herself, a gap — six hours she cannot remember, a dramatic event whose center she was but whose experience she never had.

What remains, forty-some years after the fact, is the mystery at the heart of the case.