She is dead. A man's wife, a boy's mom: She is dead. This hard, unchangeable fact begins ''Mother, Come Home,'' and the rest of the story is how the pair left behind try to deny it -- through fantasy, through self-deception, and worse. Paul Hornschemeier's graphic novella is deserving of the word masterpiece without reservation. The storytelling is a marvel of invention, the muted colors the hue of heartbreak, the tone full of understanding and grace but never maudlin. The shattering, infuriating, open-to-interpretation climax will haunt you for days, if not longer. The less said about this thing, the better, for it only leaves more for you to discover. But ''Mother'' is truly wonderful.