By the time I make it to the gate, Vladimir is on his knees in the snow, bag open at his side, and looking forlorn. Vervain is standing a few feet back from the gate, one massive clawed hand on his chin, looking surprisingly pensive.

The Ice Gate glimmers in the early light, sheathed in frost. Vladimir huffs on the surface and watches his breath freeze into tiny ice-particles. But his hand on the gate has at yet produced no reaction – the gate lies still behind its frozen cloak, the crack as dark as blood.

Vervain draws back his head and roars, commandingly. Stubborn gates, especially the newer ones, have been known to submit when faced with Vervain’s special angry tone. I put my fingers in my ears: Vladimir winces theatrically and mouths, "A little warning, next time?" as the echoes begin to fade away among the peaks. The gate creaks a little as the sun begins to rise properly and warm it, but otherwise nothing.

"You and your big mouth," I say, scathingly, as a mini-avalanche cascades down over a nearby ridge. Vervain scowls.

Vladimir says something in Ancient that makes the air around the gate smell like melting chocolate, and dashes a handful of ground silver at the ice. The gate shudders, and the rime of frost across its surface melts, running down in a stream to gather in a small, sparkling pool at the base. Vladimir sighs.

I am about to suggest that he tries a different combination, perhaps gold rather than silver (not that I know a thing about how the gate cures work…but I want to feel useful somehow) but my attention is caught by movement in the slick gate surface. Like a reflection of the moon in water, or the sudden flicker of fish beneath the skin of a frozen pond. A face is looking out from within the Ice Gate, with white eyes that glow and blink, and short, sharp fangs that stand out sharply against the sky-coloured fur on his muzzle…

"Kyru!" I shout, and he presses one thin, needle-clawed hand up against his side of the ice, looking out at me with wild, distracted concern. Vladimir pushes his palm up to match his friend’s. Kyru is silent, trapped behind the gate, unable to travel through it. But his reason for being there is plain: like us, he is overcome by concern for his friends. If we can’t fix it, it’s very unlikely Kyru will ever make his way back to the Nexus, and if he does, he’ll have to take the long way around, navigating gate by gate, trying to locate another route that will end up with us. More travellers have got lost that way than any other. My eyes meet with his and I know how mournful I must look.

Kyru, I should explain, is one of the old ones, from the time a few centuries before my parents were born. His race still sport the vestigial remains of sabre fangs, and their pelts are painted wild colours that were in the world when it was made new. Taloned like eagles and, in some cases, winged like them too, Kyru’s people are the most magical race in the Nexus. Kyru himself is rather a rebel amongst his kind, because he loves new technology more than sorcery and has embraced the twenty-first century like a brother. Plus, he’s very, very cute. A shame he only likes cheetah-girls with spotted hides and legs up to their armpits.

Only now, he looks like a lost kitten as he mouths at me from behind the gate.

What’s happening? he asks, and I shrug and shake my head dumbly. His shoulders slump, and he mimes drawing a sharply-taloned finger across his throat. Dead. The gate is dead.

I try shaking my head again in negation, but Kyru is watching as Vladimir snarls out a curse and slams his fist against the gate arch. He’s giving up.

"Come on, Lupa my love," he whispers, as Vervain comes up behind me and puts an arm around my shoulders. Numb with cold and with Kyru’s pleading eyes locked forever in my mind, for once I don’t care and I turn my face against Vervain’s shoulder. I don’t want to see Kyru again as he leans against the barrier and raises one hand in a farewell wave. "Let’s just go home, eh?" Vladimir continues, his voice hoarse. "Have some coffee. Get warm."

Once again (and believe me, for this to happen twice in one day is practically unheard of) I am stopped as I am about to speak…because I feel warmer already, suddenly, as if someone has just ignited a huge oil tanker about six feet in front of me. I look up, peering over Vervain’s shoulder, and nearly have a heart attack as wide, slit-pupilled amber eyes in a pale golden-furred face blink at me in wonder.

I can’t help it: I squeak in a most un-Lupa-like manner and scrabble away from Vervain, who turns sharply in confusion.

"What? What is it…oh!"

He exhales abruptly in relief. "Valentin!"

Valentin Mikhail utters a delighted, purring trill at being recognised, and bounces. His vast, gull-like wings beat once, throwing up clouds of powdered snow at his feet. Vladimir, who gets caught in the shower, laughs and brushes ice-crystals out of his whiskers. I gather myself and approach him as he sets up purring like a lawn mower, happy to be back with his family again.

Valentin is the throwback to Kyru’s kind in Vladimir’s family. And when I say throwback, I mean in a no-speaka-da-lingo and no-weara-da-clothes sort of way. He sees me, rumbles happily in recognition and shoves his huge, blunt head under my chin by way of greeting. He feels like he’s been basking in the sunshine for days, his pelt is so warm. I try not to sneeze as his rough golden mane gets up my nose.

Vladimir taps his brother on the arch of his wing, and Valentin turns obediently.

An odd sort of sign-language conversation ensues. Vladimir, his face twisted into a theatrical mask of misery, points at the crack in the gate. Valentin’s muzzle wrinkles into folds of tawny velvet: he can see the problem and doesn’t care for it. Vladimir then points at his open bag, still with vials and herbs spilling out of it, and shrugs. Valentin snuffles at the bag, looks at the dripping gate, and growls, deep in his throat. Vladimir then draws his attention to Kyru, who is still standing on his side of the gate.

Valentin seems thoughtful : or possibly he is merely wondering whether he will make it back to the Serengeti in time to kill a zebra for dinner, who can tell? Then he shoulders Vladimir back, cheerfully, and flares his huge white wings in exuberance. I’m starting to pick up on how Valentin-speak works, now. That particular motion means, step back, brother. Everything’s gonna be fine. You’ll see.

Valentin steps up to the gate and purrs to himself. His tufted tail slaps wetly against the melting ice, as if trying to attract the gate’s attention. Then, seemingly uncaring of the freezing temperatures against his thin, African fur, he proceeds to rub himself along the length of the gate, purring all the while as his fur darkens with water and his feather gleam in the wet.

Vervain and I watch, unsure of what he’s doing or of what to expect, but Vladimir is waving to Kyru, cheerfully, and Kyru’s moon-pale eyes are alight with hope. Valentin chirrups enticingly and nuzzles at the break in the ice. His wings arch out at his back and begin to beat, forcing cold air into motion around him. A wind springs up, and before another minute has passed a gale begins to howl.

I look at Vladimir, his black mane whipped up in the maelstrom. "Cover your eyes!" he bellows.

So I cover them, seeing with my last glimpse Vervain putting on a pair of Ray-Bans and looking supercilious. The wind roars in my ears for a few moments more, and then there is a rumble as of thunder directly overhead –

- and suddenly the wind drops. The air on my hands feels warm, so I lower them from my eyes.

The first thing that leaps out at me is that the Ice Gate is mended. The gateway shimmers in the sun, unblemished and open. Kyru bounds through it as I watch, tail switching, lynx-ears sharp and alert. The second thing is that Valentin, simple and instinctive as he may seem, has obviously inherited the family sense of humour.

Our little patch of mountain-top on which we stand has abruptly become a Garden of Eden. Around the frozen Ice Gate, improbably, a six-foot square meadow has sprouted, complete with tiny flowers and hopping bunnies. A miniature rainbow arches from the ground to meet the top of the gate. Butterflies dance dizzily about our ears.

"Valentin," admonishes Vervain, removing his Ray-Bans, "you have about as much taste as a cheap Easter card."

Valentin, who is currently sneaking up on one of the ickle fluffy bunnykins with his wings folded flat, pays him no attention. Vladimir pats Kyru on the back in relief.

"That your brother?" Kyru asks as Valentin pounces on the bunny and proceeds to tear it noisily in half.

"That’s him," says Vladimir, happily.

Valentin, muzzle red, lopes up to me and drops the butt-end of the rabbit at my feet. I resist the urge to bat him on the nose with a rolled-up newspaper, and smile weakly at him instead. "Yes! Uh…very nice. Thank you. I’ll eat it later."

Vladimir watches as Vervain flips out his mobile, obviously calling for his ‘copter to come and get him, and chuckles at the antics of Kyru and Valentin as they play together in the new grass, the golden lion-angel and the ice-blue lynx.

"Come on, Lupa. Let’s go home."

Maybe I was wrong. Us cats and dogs aren’t so very different, really.

Valentin bounds up to me and swipes at my arm with a paw. His eyes gleam.

"I am not!" I explode, causing Vladimir to stare at me as if I’ve gone mad. Valentin flirts his tail and bounces off, with me in hot pursuit. "Come back here you flying feline freak!"

"Wolves," says Vervain, strolling over to his brother. "Can’t live with them…can’t live without…no, wait. I could live without them."

"I couldn’t," says Vladimir, fondly, watching the resulting chase as the sun gleams from the mended gate.