These days we’ve been so often disappointed and betrayed by real-life “heroes” – reform-minded politicians who wind up just as corrupt as the hacks they’ve condemned; sports stars caught taking performance-enhancing drugs or beating their spouses, or both; religious leaders brought down by scandal of one sort or another – that it seem especially cruel to be robbed now of one of history’s most honorable, though fictional, protagonists.

Spoiler alert: If you haven’t heard about the shocking twist to Harper Lee’s novel, “Go Set a Watchman,” which goes on sale today, stop reading now.

Anyway, the book depicts Atticus Finch – the crusading lawyer of author Lee’s "To Kill a Mockingbird" who battled racism in a small town in 1930s Alabama while defending a black man wrongly convicted of raping a white woman – as an aging segregationist who attended a Ku Klux Klan meeting.

Atticus Finch a bigot? It’s as if Winnie the Pooh were busted for operating a meth lab, or Captain Ahab joined a People for the Ethical Treatment of Animals protest.

Much mystery continues to surround the timing of “Go Set a Watchman,” which Miss Lee supposedly penned before “To Kill a Mockingbird” but was encouraged to rewrite by her editor from a different point of view.

“To Kill a Mockingbird” wound up winning the Pulizer Prize for fiction in 1960, while “Go Set a Watchman” apparently languished in a dusty bin for decades before it was mysteriously “discovered” not long ago.

The hero of “Mockingbird” went on to become such a beloved figure – rated by Book Magazine as among the top 10 best characters in fiction since 1900 – that “Atticus” has for years been a popular baby name, as has “Harper.” The American Film Institute voted Atticus Finch, portrayed by Gregory Peck in the 1962 film adaptation, "the greatest hero in American movies."

Generations of high school students have read “Mockingbird” and learned lessons about the honor of Atticus.

Many modern-day lawyers said “Mockinbird” inspired them to go into the legal profession. Would they say the same thing after reading “Watchman”?

Some critics say the new portrayal of Atticus Finch is more realistic, especially considering the racial tensions that persist today, but we’ve always held the idealistic, if fantasy character, close to our hearts.

Let’s hope nobody “finds” a new version of “The Catcher in the Rye” depicting Holden Caulfield as a venture capitalist or of “A Tale of Two Cities,” in which Sydney Carton lets Charles Darnay go to the guillotine.

It would have been a far, far better thing if “Watchman” had stayed buried in storage.