“Doctor Izard,” by Anna Katharine Green, unfolds as a complex mystery interwoven with themes of identity, deception, and redemption. The story begins in the somber setting of Ward 13 of a hospital, where two men lie seemingly at death's door. One of these men, designated as No. Thirteen, is the observer through whose eyes the initial drama unfolds. The other, No. Twelve, is the recipient of a mysterious visit from a stranger.