A few months after the world ended Sam lost his cat. She was not his cat in the same way that his friends, relatives, and possessions were once his; she was his cat because they knew each other and that meant a lot when there weren’t a lot of others left to know anymore.

Sam paced the perimeter of his camp, kicking at the scrub brush. At the halfway point he leaned on the dessicated trunk of a tall spruce and gathered his strength, sucked in a lungful of air and cried out, “Eileen! Come on, kittykittykit–.”

The exertion triggered a coughing fit, bringing him to his knees while a sea of sparkles flooded his vision. It would be at least a few minutes before he’d be ready to try a stunt like that again. There was a rustle in the distance, enough to prick up his ears. She couldn’t be in any better shape than he was. CO2 levels might have been lower here than they were in the cities—the saving grace for him (and Eileen) but he still had trouble exerting himself for more than a few seconds before the headaches started.

The stack of oxygen tanks next to Sam’s tent made the camp look like a well-stocked survival redoubt. Rows and rows of scarce oxygen, the cure to what ailed him and the rest of the world—and Eileen wherever she was. He’d dutifully resisted cracking the seal on even one them. That’s how it starts, one exception begets another and before long you might as well not have had any rules to begin with. If the rest of the world could have stuck to a basic set of rules he and Eileen wouldn’t even be in this position.

Sam had one simple rule: No access to the tanks until he found a way to refill them.

Anything else would be a capitulation. An admission to the universe that he was content to idle his time away and accept his death.

A weak mew drifted through the clearing.

Sam grabbed a withered shrub and shook it with just enough force to make noise. Another, weaker mew came from off near the tanks. He pulled himself up to his feet, stars still dancing at the edges of his vision, the dull thunking in his head amplified. A few agonizing steps were all he needed to take. Then he’d be close to the tanks, closer to wherever Eileen was hiding.

“It’s okay, you idiot cat, I’m coming,” he mumbled.

When Sam first set up camp in the clearing, atmospheric oxygen levels had been high enough for him to perform basic tasks. He was puttering around securing the oxygen tanks when Eileen had come strolling through like she owned the place, field mouse in her teeth, proud and loud. He made a trill whistle and her eyes lit up with an eerie comprehension. She dropped the mouse at his feet and nudged it with her paw. Unexpected tears filled Sam’s eyes and he found himself reduced to a sobbing mess by the gesture. Eileen, being a cat, purred in response. She pushed her little body against his legs, revving her engine, nosing him. She was the only living thing he’d seen since the world fell apart, back then he’d only just escaped from the city. The odd plane still flew overhead. It was still possible to pretend the catastrophe could reverse course, but that was before the air got so thin that shouting was enough to bring him to his knees.

Sam hobbled to the stack of tanks, bracing himself against the straps that held them together. He stepped around to see Eileen laying on her side, glaring in his direction. Sam sat down next to her and ran his hand along her dirty fur.

“I could have run a line into our tent, you know?” He said, staring up at the sky. “I didn’t want to make it too easy to use all the air.”

She mewed again and Sam felt the vibrations of a weak purr as she pushed her head against his leg. Sam ran his knuckle along the bridge of her nose. He eyed the latch he would have to unclasp to free one of the tanks, then the coil of rubber hose and the clamps and the nozzle.

Sam strained to move Eileen onto his lap and succeeded in getting her most of the way there.

Together they slept.