THE SECRET OF THE MISSING GRAVE, by David A. Crossman, Down East Books, Camden, Maine, 1999, 184 pages, hardcover, $16.95.

I’ve just discovered a real gem of an impossible-to-put-down Maine mystery book: David Crossman’s “The Secret of the Missing Grave.” Be warned that if you’re anything like me you’ll find this suspenseful volume as fascinating as your child will. To add to its considerable appeal this fictitious story is set in a very real island locale. The building where much of the action takes place is a bed and breakfast you may want to check out this summer.

The suspense begins when Ab hears some disquieting nocturnal sounds in the bed and breakfast where her family is spending the summer. She hears mournful, raspy breathing, followed by a series of metallic footsteps. When she tells adults about the sounds, they chalk them up to her imagination.

But after he hears about the noises, Ab’s faithful companion, Bean, a year-round island resident, gets his mother to tell the two teen-agers about the legend of that old house. It and its next-door neighbor were built by business partners and connected by an underground tunnel. The partnership soured, leading to a Romeo-and-Juliet romance between the children of these businessmen. The granddaughter, an eccentric recluse, was believed to have left a mysterious treasure in the hidden tunnel.

Of course that cryptic tale is all it takes to set two adventurous, imaginative teens off on a treasure hunt. Never mind that generations of islanders have unsuccessfully searched for the tunnel.

Ab and Bean, more scientific than their predecessors, locate the tunnel and the complicated mechanism that works it. They also discover that it is still in active use. Just then both youngsters’ parents decide that they’re putting themselves in too much danger and say that they can’t enter the Webster House basement or spend unsupervised time together. Does this deter our protagonists? You’ll have to read the book to find out.

“The Secret of the Missing Grave” is finely crafted. Suspense builds neatly from chapter to chapter, and the ending is richly satisfying.

One other real charm to the book is the relationship between the two chums. Puberty has made changes in their perception of each other and added an awkwardness to their formerly easy friendship. In Bean’s words, “When she left last year she was just Ab. Now she’s thirteen and a girl all over the place.” What a refreshing change from the pseudo sophistication of television!

This authenticity comes naturally. Crossman, a Vinalhaven native now living in Friendship, wrote the book when he was in Egypt and homesick for his native Maine. For his first children’s mystery he drew on his memories of his island youth. “Much of it is really my growing-up years.”

The legends captured in the book are those of his childhood island. Crossman himself spent hours searching for the elusive tunnel. Unable to locate it, he began to wonder what would have happened if his quest had succeeded.

Each chapter ends with a cliffhanger. The book concludes with a real teaser. Just as all the loose ends are tied up, we are told that something strange has washed up at Indian Creek.

If the response to “The Secret of the Missing Grave” is good enough Crossman will write the sequel. Currently he’s visiting intermediate-grade classrooms to get ideas. “I don’t know what it is that washed up.”