Behind him sounded the casual notes of a . "Ser Moon Moth Thissell, you stand engrossed in thought."

Thissell turned, to find beside him a Cave Owl, in a sober cloak of black and gray. Thissell recognized the mask, which symbolized erudition and patient exploration of abstract ideas; Mathew Kershaul had worn it on the occasion of their meeting a week before.

"Good morning, Ser Kershaul," muttered Thissell.

"And how are the studies coming? Have you mastered the C-Sharp Plus scale on the ? As I recall, you were finding those inverse intervals puzzling."

"I've worked on them," said Thissell in a gloomy voice. "However, since I'll probably be recalled to Polypolis, it may be all time wasted."

"Eh? What's this?"

Thissell explained the situation in regard to Haxo Angmark. Kershaul nodded gravely. "I recall Angmark. Not a gracious personality, but an excellent musician, with quick fingers and a real talent for new instruments." Thoughtfully he twisted the goatee of his Cave-Owl mask. "What are your plans?"

"They're non-existent," said Thissell, playing a doleful phrase on the . "I haven't any idea what masks he'll be wearing and if I don't know what he looks like, how can I find him?"

Kershaul tugged at his goatee. "In the old days he favored the Exo Cambian Cycle, and I believe he used an entire set of Nether Denizens. Now of course his tastes may have changed."

"Exactly," Thissell complained. "He might be twenty feet away and I'd never know it." He glanced bitterly across the esplanade toward the mask-maker's shop. "No one will tell me anything; I doubt if they care that a murderer is walking their docks."

"Quite correct," Kershaul agreed. "Sirenese standards are different from ours."

"They have no sense of responsibility," declared Thissell. "I doubt if they'd throw a rope to a drowning man."

"It's true that they dislike interference," Kershaul agreed. "They emphasize individual responsibility and self-sufficiency."

"Interesting," said Thissell, "but I'm still in the dark about Angmark."

Kershaul surveyed him gravely. "And should you locate Angmark, what will you do then?"

"I'll carry out the orders of my superior," said Thissell doggedly.

"Angmark is a dangerous man," mused Kershaul. "He's got a number of advantages over you."

"I can't take that into account. It's my duty to send him back to Polypolis. He's probably safe, since I haven't the remotest idea how to find him."

Kershaul reflected. "An out-worlder can't hide behind a mask, not from the Sirenese, at least. There are four of us here at Fan -- Rolver, Welibus, you and me. If another out-worlder tries to set up housekeeping the news will get around in short order."

"What if he heads for Zundar?"

Kershaul shrugged. "I doubt if he'd dare. On the other hand --" Kershaul paused, then, noting Thissell's sudden inattention, turned to follow Thissell's gaze.

A man in a Forest Goblin mask came swaggering toward them along the esplanade. Kershaul laid a restraining hand on Thissell's arm, but Thissell stepped out into the path of the Forest Goblin, his borrowed gun ready. "Haxo Angmark," he cried, "don't make a move, or I'll kill you. You're under arrest."

"Are you sure this is Angmark?" asked Kershaul in a worried voice.

"I'll find out," said Thissell. "Angmark, turn around, hold up your hands."

The Forest Goblin stood rigid with surprise and puzzlement. He reached to his, played an interrogatory arpeggio, and sang, "Why do you molest me, Moon Moth?"

Kershaul stepped forward and played a placatory phrase on his . "I fear that a case of confused identity exists, Ser Forest Goblin. Ser Moon Moth seeks an out-worlder in a Forest Goblin mask."

The Forest Goblin's music became irritated, and he suddenly switched to his . "He asserts that I am an out-worlder? Let him prove his case, or he has my retaliation to face."

Kershaul glanced in embarrassment around the crowd which had gathered and once more struck up an ingratiating melody. "I am sure that Ser Moon Moth --"

The Forest Goblin interrupted with a fanfare of tones. "Let him demonstrate his case or prepare for the flow of blood."

Thissell said, "Very well, I'll prove my case." He stepped forward, grasped the Forest Goblin's mask. "Let's see your face, that'll demonstrate your identity!"

The Forest Goblin sprang back in amazement. The crowd gasped, then set up an ominous strumming and toning of various instruments.

The Forest Goblin reached to the nape of his neck, jerked the cord to his duel-gong, and with his other hand snatched for his scimitar.

Kershaul stepped forward, playing thewith great agitation. Thissell, now abashed, moved aside, conscious of the ugly sound of the crowd.

Kershaul sang explanations and apologies, the Forest Goblin answered; Kershaul spoke over his shoulder to Thissell: "Run for it, or you'll be killed! Hurry!"

Thissell hesitated; the Forest Goblin put up his hand to thrust Kershaul aside. "Run!" screamed Kershaul. "To Welibus's office, lock yourself in!"

Thissell took to his heels. The Forest Goblin pursued him a few yards, then stamped his feet, sent after him a set of raucous and derisive blasts of the hand-bugle, while the crowd produced a contemptuous counterpoint of clacking .

There was no further pursuit. Instead of taking refuge in the Import-Export office, Thissell turned aside and after cautious reconnaissance proceeded to the dock where his houseboat was moored.

The hour was not far short of dusk when he finally returned aboard. Toby and Rex squatted on the forward deck, surrounded by the provisions they had brought back: reed baskets of fruit and cereal, blue-glass jugs containing wine, oil and pungent sap, three young pigs in a wicker pen. They were cracking nuts between their teeth, spitting the shells over the side. They looked up at Thissell, and it seemed that they rose to their feet with a new casualness. Toby muttered something under his breath; Rex smothered a chuckle.

Thissell clacked his angrily. He sang, "Take the boat offshore; tonight we remain at Fan."

In the privacy of his cabin he removed the Moon Moth, stared into a mirror at his almost unfamiliar features. He picked up the Moon Moth, examined the detested lineaments: the furry gray skin, the blue spines, the ridiculous lace flaps. Hardly a dignified presence for the Consular Representative of the Home Planets. If, in fact, he still held the position when Cromartin learned of Angmark's winning free!

Thissell flung himself into a chair, stared moodily into space. Today he'd suffered a series of setbacks, but he wasn't defeated yet, not by any means. Tomorrow he'd visit Mathew Kershaul; they'd discuss how best to locate Angmark. As Kershaul had pointed out, another out-world establishment could not be camouflaged; Haxo Angmark's identity would soon become evident. Also, tomorrow he must procure another mask. Nothing extreme or vainglorious, but a mask which expressed a modicum of dignity and self-respect.

At this moment one of the slaves tapped on the door-panel, and Thissell hastily pulled the hated Moon Moth back over his head.