Rudy seized a shorter pole, and expertly kept the bow from nudging into the stone sides. Sometimes they all had to duck their heads to get under a low spot.

“You saw Dmitri yesterday leading the band in the park,” Rudy told the other two boys. “He’s one of the few who know these drains as well as Elena and I.”

In places, the stone ceiling dipped so close to the rushing water that Bob worried they wouldn’t be able to pass. But each time they made it, and there was no sign of pursuit behind.

“Where’s Pete?” Jupiter asked Elena, who crouched silently beside him.

“Waiting for us,” she answered. “The boat wasn’t big enough to bring him. Besides, he’s better off where he is. I wanted him to get to safety, but he wouldn’t until he had found you or given up hope of rescuing you.”

That sounded like Pete, all right.

“Where are we now, Dmitri?” Rudy called. “I’m afraid I’m lost.”

“We are making a circle to reach the hiding place,” Dmitri replied. “We’ll be there in five minutes.”

They came to another chamber where several of the drain tunnels met. This time Dmitri selected the one in the center and pushed forward. This tunnel was larger. They could sit upright now. They continued on until suddenly they saw a pinpoint of light ahead.

“Someone’s ahead of us!” Bob said in alarm.

“If we’re lucky it is Pete,” Elena said. “That’s the meeting place.”

The light grew brighter and they could see it came from an electric lantern. The lantern had been placed in a big hollow, almost like a shallow cave, in the side of the storm sewer. Pete was crouched beside it and he welcomed them enthusiastically.

“Am I glad to see you!” he exclaimed. “I was getting lonely here. Some rats wanted to keep me company but I chased them off.”

Dmitri steered the boat close to the side, and Rudy wedged a rope between two rocks to hold it. Then they clambered out into the cavelike hollow. The raggedness of natural rock here contrasted with the smoothly fitted stones out of which artisans many centuries before had built the city’s storm drains.

“The builders found this natural underground cave when they built the drains,” Rudy explained as they flopped down on the rock to rest. “It was easier to leave it than to wall it off. I discovered it years ago. We had a secret society that explored these drains, even though our father did his best to stop us. We never realized how useful our childish games were going to be.”

“Now we must take council,” Elena said, looking worried. “I don’t think our original plans will work.”

“First tell me what has happened,” Rudy requested. “Dmitri, how do you come to be here?”

“I was at your father’s house when the guards came to arrest him,” Dmitri said. “I escaped through the secret door. I lingered and listened. The captain taunted your father, saying, ‘Your traitor son has been captured and soon you will all stand trial.’ But he said nothing about Elena. I hoped she had escaped.

“I knew your plans, so I entered the storm sewers to see if I could meet Elena and help her. It was raining, the drains were running water, so I took the old boat we kept hidden.”

“Yes, and Dmitri did find us, just in time,” Elena said. “Pete and I escaped from the palace the way we had planned, and came down here. We met Dmitri and decided to stay on watch as long as we could, just in case you escaped. We figured your only chance would be down from the dungeons. Well — here we are. Now we must talk about the future.”

“First let us listen to the radio,” Dmitri said. “Pete, you have it.”

“Oh, yes.” Pete pulled a tiny transistor radio out of his pocket. “I turned it off because I couldn’t understand what they were saying.”

Dmitri snapped it on. A stream of words poured out, in Varanian, followed by a band playing military music. Elena translated for The Three Investigators.

“It said for all citizens of Varania to stay by their radios and television sets for an important announcement at 8 o’clock this morning. It said the announcement is of supreme importance. It was the Prime Minister’s voice — recorded, of course.

“That means that at 8 o’clock they are going to announce that a foreign plot has been uncovered — that is you three — and that Prince Djaro is implicated and that Duke Stefan is remaining Regent until further notice. Of course, they didn’t expect you to escape — they expected to be able to hold a public trial and show those cameras and everything and then expel you from the country and put Rudy and Father in jail and, oh, everything unpleasant they can think of.”

“Gosh,” Bob said in dismay. “We’ve just made it worse for Djaro by coming here. It would have been better if we’d stayed home.”

“No one could foresee that,” Elena said. “Now we must get you to safety at the American Embassy. Right, Dmitri?”

“Correct, Elena.”

“But what about yourselves? And your father? And Djaro?” Jupiter asked.

“That is for later,” Elena said and sighed. “I’m afraid their plans are too well prepared for us. If we could rescue Djaro — if we could arouse the people of Denzo to his danger — we could foil the plot. But as we have already said, Duke Stefan and his gang have everything in their favor.”

“Yes,” Dmitri agreed, “we must get you three to safety, then see what we can do about ourselves. Our cause is lost, I’m afraid. But perhaps there will come another day. Now let us start. It is already daylight outside. In an hour the radio and television will be broadcasting the Prime Minister’s announcement. By then we hope you will be safe in the American Embassy.

“So follow me. From here we go on foot. The boat will not take us all.”

He dropped down into the rushing water below. One by one the others followed, holding on to the blanket-strip rope. With heavy hearts the little group made its way again through the storm sewers of Denzo.

IN THE CITY above them the rain had stopped, and the water in the drains became shallower. Soon it was only to their ankles and they could move freely. They passed more chambers where several dark tunnels met, but Dmitri seemed to know his way.

“We will emerge in the block where the American Embassy is located,” Dmitri called back once. “Pray to heaven they do not have it guarded.”

They walked for what seemed a long time, though time was hard to tell in the tunneled darkness. Certainly they covered eight or ten blocks. They came to another round chamber which marked a manhole above, and abruptly Dmitri stopped.

“What is it?” Rudy called. “We have two blocks yet to go.”

“Something tells me they will surely have the spot we are heading for guarded,” Dmitri said. “They will guess that is where we would go, and nab us like mice coming out of their hole. If I am correct, we are now under the flower market, behind the Church of St. Dominic. They won’t be looking for us here. We can slip up to the American Embassy from the rear.”

“I believe you are right,” Rudy agreed. “All right, we can’t stay down here the rest of our lives. Let’s go up.”

Iron rungs in the rocks led upward. Dmitri reached the top, put his shoulder beneath the manhole cover and heaved.

The iron cover lifted, and clanged to the cobbled street. Dmitri scrambled out.

“Come up quickly!” he cried. “I’ll give you a hand.”

Dmitri’s strong hand pulled Elena up, then Bob. Bob blinked in the unaccustomed daylight. It was a cloudy day, the streets glistening with the night’s rain. They were in a narrow alley with old houses rising on each side. Many stalls lined the alley, and vendors in quaint costumes were arranging bright flowers and fruit for the hoped-for business of the day. They looked with amazement as the rest of the bedraggled little party came scurrying up out of the drains.