Wittman on the Eastern Shore of Maryland. The ray was also directly in the path of an odd-looking cruising houseboat, the Spindrift, that had just rounded the north point of Poplar Island and entered the channel.

The sting ray's color was an olive brown, so dark in tone that he looked like wet black leather. He was roughly diamond-shaped, like a kite, with rounded sides. He had a long, slim tail that carried vicious barbs along the base of its upper side. It was from the barbs, which served as defensive weapons, that the name sting ray, or stingaree, derived. The ray was harmless to men—unless one chanced to step on him as he lay resting on the bottom ooze. At such rare times, his tail would lash up, inflicting a serious and painful wound.

A tiny crab, hatched only a week before, swam upward toward the gleaming surface, his churning legs making a slight disturbance. The ray sensed the small vibrations and instantly changed course, speeding through the water like a fantastic spaceship of the future. Intent on the crab, the ray ignored the stronger vibrations caused by a pair of outboard motors and a long, flat-bottomed hull. Not until the crab was within reach did the ray sense imminent danger. With a single flashing movement, he snatched the crab and flung himself upward through the shining surface and into the air.

Rick Brant, at the helm of the cruising houseboat, saw the ray break water and he let out a yell. "Scotty! Look!"

Don Scott, asleep at full length on the houseboat's sun deck, which was also its cabin top, awoke in time to see the dark shape reenter the calm water. "Stingaree!" he exclaimed.

Rick had never seen an area more teeming with life than Chesapeake Bay, unless it was the jungles of the South Pacific. Books, guides to eastern land and water birds, regional fish and reptiles, rested on the cabin top before him, along with a pair of binoculars. He had used them all repeatedly, identifying eagles, wild swans, ospreys, wild duck and geese, terrapin, snapping turtles and water snakes, as well as a horde of lesser creatures. Trailing lines over the houseboat stern had captured striped sea bass, called "rockfish" locally, a species of drumfish called "spot" because of a black spot on the gills, pink croakers that the Marylanders called "hardheads," and the blue crabs for which the bay is famous. He had seen clam dredges bringing up bushels of soft-shelled, long-necked clams that the dredgers called "manos," and he had seen the famous Maryland "bugeyes" and "skip-jacks"—sailing craft used for dredging oysters. The boats were not operated during the oyster breeding season from the end of March until September.

Rick's interest in the life of the great bay was to be expected. As son of the director of the world-famous Spindrift Scientific Foundation, located on Spindrift Island off the coast of New Jersey, he had been brought up among scientists. The habit of observation had developed along with his natural—and insatiable—curiosity.

The tall, slim, brown-haired, brown-eyed boy was completely happy. He enjoyed casual living, especially on the water, and life on the Spindrift couldn't have been more casual. He was dressed in a tattered pair of shorts and a wristwatch. Once, in the cool of the evening, he had slipped on a sweat shirt. Otherwise, the shorts had been his sole attire while on board since leaving his home island a few days before.

Scotty, a husky, dark-haired boy clad only in red swimming trunks, came down the ladder from the cabin top and stood beside Rick in the cockpit. "Now that you woke me up to look at a fish, suppose you tell me where we are? Last thing I remember, we were passing under the Bay Bridge off Annapolis."

"That's Bloody Point Lighthouse behind us," Rick said. "Poplar Island is on the starboard and the Eastern Shore to port. That black thing sticking up ahead of us is a light buoy. When we reach it, we should be able to see the range markers into Knapps Narrows."

Scotty checked the chart on the table hinged to the bulkhead formed by the rear cabin wall. "What time is it?"

Rick glanced at his watch. "Five after six. Time for chow. Want to rustle up something? Or shall we eat at Knapps Narrows? The cruising guide says there's a restaurant there."

"Let's eat out," Scotty replied promptly. "I'm sick of my cooking—and yours. I'd like some Maryland crab cakes like those we had in Chesapeake City."

Rick remembered with pleasure. "Suits me."

"Think we'll get to Steve's tonight?" Scotty asked.

"I doubt it. We probably could reach the mouth of the river about dark, but then we'd have to navigate up the river and into a creek before reaching Steve's. I don't want to tackle these Chesapeake backwaters at night."

The destination of the houseboat was the summer cottage of Rick's old friend, Steve Ames, who was also a chief agent of JANIG, the top-secret Federal security organization. The boys, and the Spindrift scientists, had worked on several cases for JANIG, starting with the adventure of The Whispering Box Mystery. Steve was responsible for Rick's ownership of the houseboat, which had been named for Rick's home island on the grounds that it was now his "home away from home."

Rick's first glimpse of the houseboat had been from the air. At the request of Steve Ames, he, Scotty, his sister Barby, and Jan Miller, daughter of one of the Spindrift physicists, had been searching the coast of New Jersey for signs of strangers in the area. Barby had spotted the houseboat, which at that time was painted a bright orange. Later, the houseboat had played a major role in the adventure of The Electronic Mind Reader, and Rick had fought for his life and the safety of the two girls in the very cabin behind which he now stood. The houseboat had been impounded by Federal authorities, and recently Steve had mentioned to Rick that it was to be auctioned. After consulting with his family, Rick had entered a bid for the boat. His bid had been the only one, and he became owner at what was close to a salvage price.

It was Rick's pride that his chief possessions had been bought with his own money, and the houseboat was no exception. Like his first plane, the Cub, he expected the houseboat to pay its own way. Rick had recovered his investment in the Cub by using it to operate Spindrift Island's ferry service to the mainland. Rick flew the scientists to Newark Airport when they had to catch planes, or he flew to Whiteside for groceries, or into New York to pick up parts and supplies. The houseboat could not be used in the same way, but he was sure he could get its price back by renting it to summer visitors to the New Jersey area. He had repainted it in two shades of green with a white top, and had made a few other improvements.

Before renting the boat, however, he intended to have an extended houseboat vacation. He and Scotty had left Spindrift Island, headed south into Manasquan Inlet, and then sailed into the inland waterway. By easy stages—the houseboat could make only ten miles an hour—they had moved down the waterway into Delaware Bay, up the Delaware River, through the Chesapeake and Delaware Canal, and into Chesapeake Bay. Now, some twenty miles south of Annapolis, the boys were nearing Steve's summer cottage.

Rick's parents, with Barby and Jan, were now on their way to Wallops Island rocket range operated by the National Aeronautics and Space Administration. Hartson Brant had business there in connection with instruments the Spindrift group of scientists had designed for measuring solar X rays. The instruments would be launched in rockets. Wallops Island was near Chincoteague, Virginia, just across the Maryland-Virginia border on the long peninsula called "The Eastern Shore" that runs between Chesapeake Bay and the Atlantic Ocean. By car, Wallops was less than two hours from Steve's summer cottage.

As soon as his business was concluded, Hartson Brant planned to drive to Steve's, where the Brants and the two girls would join Rick and Scotty for