The Four Waterfalls is a modest walk by Blue Mountains standards. Rose, their hostess, assures them that it’s flat and only an hour or so, plenty of time before Anne and Julia leave for the coast. And it isn’t a National Park, which makes it one of few places where Horatio, Rose’s ageing collie, can come with them.

Flat is not how Anne would describe it, as she puffs her way up the track from the first waterfall, trailing valiantly after Julia, Rose and Rose’s partner Kep. But she supposes it’s all relative. What’s a flight of 100 rough-hewn steps if you’re used to the thousand metre drop into the Jamison Valley?

And it’s beautiful, there’s no doubt about that. Green and lush, and everywhere the tinkle, drip and gurgle of water, wetness unimaginable to an Adelaide soul. For a time the track is level and Anne plods along happily next to Horatio. He is an affable companion, though a little stiff in the joints. Anne knows how he feels.

The descent to the second waterfall is steeper and Horatio is beginning to move very slowly, hesitating at every rock or awkward drop. Rose drops back to encourage him. At the bottom they stop for a good rest, sprawling on a miniature sandy beach, sharing trail mix and paddling in the creek. Obviously the walk is going to take longer than an hour, but never mind, they’re on holiday.

Finally they gather their belongings and lace their boots. But Horatio is reluctant to get up, and even when he’s on his feet he shows no sign of wanting to move. Finally, with Rose pushing him gently and the others cooing encouragement, he starts to walk. For a short time all is well, with some assistance from behind he makes it up the first rise.

But another few hundred metres and the track climbs steeply again. More steps. Horatio stops altogether and lies down. Nothing that Rose says has any effect. Eventually she and Julia try carrying him, Julia going up backwards with his head and forequarters while Rose comes along behind with his hindquarters and tail. Horatio utters a few very small noises of restrained protest and regards them with a pained expression. Rose hopes that it is only his dignity that is suffering. Huffing and puffing they lower him to the ground.

‘Come on boy,’ they say. ‘You can do it.’

But he simply lies in the track looking at them.

They confer. Better to go back or better to go forward? Unfortunately they are pretty much at the halfway mark.

‘Do you think we can get a rescue helicopter in for a dog?’ Anne asks.

‘For a price,’ Rose says.

They decide to go on.

After a few minutes rest Horatio rises valiantly to his feet and they manage in good order for a stretch. But Horatio is getting slower and slower.

At the next rise he stops again, he has had enough. He gazes at the women with infinite patience.

‘Okay,’ says Rose. ‘We can do this.’