TROY DUFFY’S original Hollywood story was a fractured fairy tale. As recounted in the documentary “Overnight,” Mr. Duffy reacted to the instant success that came with a multimillion-dollar deal with Miramax for the thriller “The Boondock Saints” by abusing his friends, family and new corporate partner, doing it all on camera, and then alienating the filmmakers who had the footage. As Cinderellas go, he was the type who would smash the glass slipper and kick Princess Charming down the stairs.

Yet a decade later the glass slipper is on the other foot. “The Boondock Saints II: All Saints Day,” the guns-and-rosaries sequel to the shoot-’em-up that almost never was, will be released on Oct. 30. Accessorized with Roman Catholic iconography and a smattering of Latin, it resurrects the fraternal assassins Connor and Murphy McManus (again played by Sean Patrick Flanery and Norman Reedus) to blow away a raft of Boston bad guys and channels Mr. Duffy’s dismay with a “self-help, 12-step, hippie generation” that would question vigilante justice. Gay jokes, Latino jokes and mayhem: Mr. Duffy is sure the fanboys will eat it up.

“I know my base,” he said.

It’s hard to argue with that statement: After Miramax cut him loose and a tiny distributor managed a feeble theatrical release, the first “Boondock Saints” went on to substantial DVD sales in seven different incarnations. (Bruce Nash of Nash Information Services said total domestic video sales have been around $50 million. Distributors generally do not release DVD sales figures.) Mr. Duffy got none of that money, thanks to his original deal, and a lawsuit over the rights to the property kept him tied up for five years. Meanwhile word of mouth (propelled by the Internet) was making it a cult movie.

Its formula  the familiar “Dirty Harry”-style appeal to the public’s indignation over crime and its affection for heroes who are “taking care of business,” as Mr. Flanery put it  made “The Boondock Saints” a guilty pleasure, one that spurs some of its fans to extremes.