“You’ve got me at a disadvantage, Mister…” Dax said, trailing off as she eyed him with apparent suspicion.

For a moment, he stroked his capacious mustache, a nervous habit that seemed to grow worse the longer he lived in the caverns. “Keru,” he said. “Ranul Keru. Lieutenant commander, U.S.S. Enterprise.”

“You’re Starfleet?” Dax said with a smile.

“I’m on extended leave.” Keru explained. “I had some…personal things to work through.” He’d stayed on the Enterprisefor some time after Sean’s death three years ago, but found little joy in stellar cartography anymore. The entire ship had become too painful a reminder of all he had lost.

Keru saw no need to share any of that with Dax, however, especially given the present circumstances.

“Well, I’m glad you’re here,” Dax told him. “You might make things go easier. If you don’t mind, I’d like you with me when I speak to whoever’s in charge here.”

“I’ll be happy to provide any help I can, especially if it’ll help rein in the madness out there.” He swept his arm to the side, ushering her toward the cave entrance.

As she descended the winding stone stairs alongside Keru, Dax reflected that it had been five years since her last visit to the winding catacombs of Mak’ala. No, notmy visit,the part of her symbiosis that was Ezri Tigan reminded her. Despite the familiar sights, sounds, and smells of the dark, rough-hewn rock faces, the high, igneous stone ceilings and dripping stalactites, and the bubbling, geothermally heated pools of mineral-rich water, she knew that all her memories of this place had come from Jadzia Dax and previous hosts.

The thing that struck her most viscerally was the tomblike darkness of so much of the place, which was lit only in the most strategic and necessary places, mainly along the stone stairways and near the frothy gray symbiont breeding pools. The blackness that enclosed the rest of the vast underground spaces felt oppressive and tomblike. Ben Sisko had angrily confronted her shortly after Ezri had become joined to Dax, telling her she could always retreat to this place to live out a challenge-free existence should life in Starfleet prove too difficult for her.

But it was clear to her now that the oppressive nature of Mak’ala, along with the obvious stolid toughness of the Guardians to whom Keru had introduced her—they were single-mindedly dedicated people who seemed to spare no effort in the constant monitoring and testing of the nutrient and mineral content of the symbiont breeding pools—demonstrated that this was no place for the weak. As Keru conducted her to a small natural dais near one of the larger pools, she reflected that it must take a special sort of person indeed to devote his entire life to the care of the symbionts, while at the same time being forever denied the benefits of joining.

When was the last time any of these people went outside and got any sun?she wondered as Keru briefly excused himself to summon his order’s leaders. While waiting for her guide to return, Dax watched as a pair of younger Guardians received a patient lesson in acidity adjustment from an old woman who knelt beside the nearest pool, dipping sampling tubes into the gently lapping gray waves. Several unjoined symbionts breached then, momentarily sending crackling latticeworks of energy across the rippling surface before disappearing once again down below. The old woman smiled in evident satisfaction, as though the symbionts had just spoken directly to her, peer to peer.

It occurred to Dax that maybe they had. Maybe the Guardians enjoyed a relationship with the symbionts that the joined could never understand. As far as she knew, no joined person had ever served as a Guardian. Perhaps after communing with the symbionts as the Guardians did, one lost all desire or capacity for joining. Perhaps selecting one path—either joining or the Order of the Guardians—forever rendered the other inaccessible.

Her reveries were interrupted by the return of Keru, who accompanied six pale, dour-faced, robed men and women ranging in age from late middle age to elderly, whom Keru introduced generically as the Order’s senior leadership. They seemed preoccupied and unwilling to spend much time in conversation, as Timor had been five years earlier. Just as she had feared, the Guardian leaders were hesitant to answer direct questions about the early history of Trill joinings, the parasites, or the lost joined Trill colony that the neo-Purists claimed had once existed on Kurl. Her explanations about the unrest that was flaring up across the planet and the government cover-up allegations recently broadcast by the neo-Purists didn’t seem to move them.

What are they so determined to hide?she wondered. Well aware of how ingrained Trill secrecy was, she had to consider the possibility that they might not even know the secrets they seemed so determined to protect.

Ranul Keru, with the assistance of a young male Guardian who introduced himself as Rantic Lan, took up the pleading on her behalf, conferring with the senior Guardians on one of the cave plateaus out of Dax’s earshot. The other Guardians kept a wary eye on her from a distance, as if afraid she might suddenly jump into one of the pools.

I wonder what Timor told them?she thought. He had been the one who had allowed Jadzia to enter the pools five years ago, after she had learned the truth about the Dax symbiont’s temporary joining to Joran more than a century earlier. It occurred to her that she hadn’t seen Timor among the Guardians gathered here today. Had he been fired or transferred for aiding Jadzia?

Several silent minutes later, Keru and the senior Guardians approached her. The eldest of them, a woman whose face and spots were almost indistinguishably pallid from lack of sunlight, approached Dax closely.

“What you have told us is troubling, Ezri Dax,” she said. “Troubling not just because of the unrest it causes our people now, but also because it incites a distrust between Trill humanoids and symbionts. Our memories, our history, our truth…these are the foundations of our society, and of joining itself.”

The old woman paused, looking uncomfortable, then continued. “But we cannot help you. We cannot concern ourselves with anything other than caring for the symbionts.”

“Do I really have to point out that it’ll be impossible for you to keep doing that—caring for the symbionts, I mean—if this place gets overrun by neo-Purist radicals?” Dax said dryly.

Dax noticed that Rantic Lan’s expression was downcast and defeated. Keru walked away from his superiors, coming to a stop facing the nearest pool, his back turned. Damn. Even he’s given up.

Then, as the six Guardian leaders began to disperse to their various tasks, the normally placid back-and-

forth wave action of the pool suddenly became tumultuous. Three, then four symbionts breached the pool’s gray surface simultaneously, followed immediately by a dozen more. The senior Guardians stopped in their tracks, transfixed. Jagged forks of lightninglike discharges sprouted, connecting each of the symbionts to one another. And to Keru.

The big man turned to face Dax again. “It seems my superiors have just been overruled. I think your questions are going to be answered.”

Dax’s heart leaped into her throat. “What do I have to do?”

A beatific smile spread across Keru’s lips. “Just swim to the very bottom of the pools. Where nobody’s ever gone before.”

Fifteen minutes later, Keru stood by the side of the pool, checking the seals on Dax’s environmental suit, retrieved from her runabout. He knew the suits were rated for marine operations and considerable pressures, but he had never been involved in putting those claims to the test. “You know this might not work, right?”

“I have to try,” she replied.