Mystery lurks in the improbably streets and houses of Ash Garden, Ind., "town with a past, city of the future." What is the hidden meaning of the bull and lobster blazing in neon over the entrance to the Steak and Lobster Inn? Can they be stylized representations of the astrological signs Taurus and Scorpio? Why are the two candidates for local sheriff named of Olaf and Magnus -- names of great weight in the history of medieval Scandinavia?

How can Olaf, the incumbent sheriff, allow such blood sports as cockfighting and bull-baiting at the county fair, which is being held on Midsummer Day? What is this mysterious religious ceremony being held by Magnus in a secret cave -- the sacrifice of a bull and the selection of a king who will god for a day? Why are some of the women wearing gold jewelery with ancient runic inscriptions, and why do all the local ionhabitants look like Vikings? Why are so many people carrying guns on Election Day?

Into this tangle of question marks wander two New Yorkers, Frank and Julian, lured 800 miles from home by mysterious messages they have been receiving from an enigmatic figure called J. Randolph Wong. They know him only by that name (which is probably not real) and a series of post-office box numbers that he changes frequently. Wong has led Julian to believe that there is a cache of ancient Viking gold hidden for nearly a millennium somewhere in southern Indiana -- and darned if Ash Garden, once they have chanced upon it, doesn't look like the modern survivor of a prehistoric Viking settlement.

This may sound like a lot of material for a 152-page book, and in fact it is; but there is more. Philip Appleman, who teaches English at Indiana University, seems to place no limits on his interests or on the material he is willing to cram into one brief novel. It is his second, by the way, though it sometimes has the flavor of a first novel. Besides writing and editing a variety of scholarly works, he has written three books of poetry and the widely acclaimed novel "In the Twelfth Year of the War." And in "Shame the Devil," he has a handful of other books conveniently if sometimes incongrusoulsy sandwiched between two covers.

Frank and Julian, treasure hunters in a strange land, earn their day-to-day living in a highly specialized form of outlawry: the ghostwriting of doctoral dissertations, particularly in the field of education. One of Appleman's virtuoso moments comes when Frank, a Columbia Teachers College dropout, takes a passage translated from an ancient Viking manuscript and puts it into educationese. The original reads: "Then came the weary portages, bending our backs for the slaughtered oxen, the scalding summer beading our skin with salt, the red-skinned skralingar's hatred harrying us in the tangled forests."

Frank, tailoring it for an imaginary doctoral committee, extemporizes a translation, and the contrast between the two passages gives us, in microcosm, the difference between two cultures: "The strategy of portaging was a mode of investigating the assumption that the role identity of oxen could be established as a dependent variable in the motivational model, the oxen having been subject to variances attributable to relative need in the preliminary studies. Heat, however, was prima facie an independent variable inversely related to group performance, and the identity concept of the indigenous inhabitants was a significant, though random, selectivity factor."

That passage is from a parchment -- one of many -- that the inscrrutable Wong has been sending for interpretation to Frank and Julian at their New York office, Confidential Services Inc. And the remarkable thing about it, besides Frank's ability to render poetry into platitude, is that it clearly describes a Viking expedition being harried by American Indians -- firsthand confirmation of what had once seemed a crackpot theory about who really discovered North America.

But of course Julian, who translates the ancient runes into English, sees more in it than the mere satisfaction of archeological curiosity: "All those centuries of piracy, pillage, slave-running, the world's greatest international blackmailers, they must have ripped off a mountain of gold, and it's all out here, somewhere, shiploads of it."

In search for gold, Frank and Julian wander into a world that reads sometimes like an Old Norse saga, sometimes like a chapter from "The Golden Bough," and occasionally like a random page from an astrological manual. It would be unfair to divulge any more of the abundant plot, but one may at least hint that along the way they both also manage to find true love -- as contrasted with the kind that had been available to them in New York.

It may seem churlish to complain that an author has given his readers too much, particularly when he does not demand an inordinate amount of reading time, but Appleman has risked such accusations -- no doubt deliberately, for his bookmanship functions at a high level. His writing is always serviceable and sometimes brilliant, and the mind that one senses behind the story is a keen one, constantly darting off in a dozen directions at once. It is when the mind comes wandering back from those dozen directions, bearing all kinds of miscellaneous loot that is poured into the story, that one begins to wonder: Has the author brought the elements of his novel together because they belong together or because they happened to interest and amuse him?