A PUBLISHER ONCE ASKED Stephen King to write a narrative to accompany a calendar. Each month a werewolf would terrorize a small town until, ultimately, a handicapped boy would come along to save the day. Stephen King being Stephen King, the idea grew into--or rather became--a full-length feature film.

Not even Stephen King can make a movie about a calender.

The werewolf schtick went through a novelette" phase on its way to becoming a box-office draw, but it would be a mistake to call Silver Bullet a story. Stories generally rely on characters and a plot.

Silver Bullet has a werewolf and gallons of blood.

One of the movie's opening shots is of a holiday picnic in Tarker's Mills, "a town where people cared about each other as much as they cared about themselves." The town's leaders are all leather-faced, identical men who go to family get-togethers and raise clear-skinned kids.

But one of them is a bit different. You see, he's kinda psychotic. He has a five o'clock shadow, the haunted eyes of the posessed. In the subtle idiom of Stephen King, that's called foreshadowing. That guy's the werewolf.

What follows is about as unpredictable and exciting as a lecture on equity vs. efficiency featuring Martin Feldstein.

Since the movie doesn't star a frumpy dog with a sad face, it stars a crippled kid with a sad face (Corey Haim). The kid zips around town in a motorized wheelchair called "The Silver Bullet," longingly watches his buddies play baseball, sneaks out of his room late at night to light fireworks and does other such adorable things.

THE KID HAS A SISTER (Megan Follows) who narrates the film from the present, set for some unexplained reason in 1976.

The sister and the kid have a relationship. The sister is jealous of the attention her brother gets from their parents, ("You always take his side because he's crippled. Well it's not my fault he's crippled!"). And the kid feels terrible when a joke he plays on his sister makes her ruin her new pantyhose.

But none of that stuff matters. It isn't very interesting, and it won't make anyone believe Silver Bullet is a real movie.

Gary Busey, who plays the lovable, hard-drinking Uncle Red, seems to understand that lines have to be timed. His performance is the movie's least tiring.

As the mother of a handicapped child, Robin Groves manages to evoke no sympathy whatsoever. She henpecks her daughter constantly, never realizing that 15-year-old girls don't like being saddled with responsibility for little brothers. To protect her son from "giving up" she tries to shelter him from tiffs with his sister and other "unpleasantness," but she does nothing to keep the 13-year-old crippled boy from racing all around town on a souped-up motorized wheelchair that blows by cars as if they were standing still. Even after his best friend is torn to pieces by the werewolf, she doesn't put an end to the boy's wandering. It all seems silly.

In the novelette which preceded Silver Bullet Steven King compares the coming of a werewolf to "the arrival of cancer, or a psychotic with murder on his mind, or a killer tornado." Judging from Silver Bullet any of those other possibilities could provide more entertainment.