The sign above Sano Electric has been buried under Martian red dust for years — nobody can read it anymore. Then again, nobody needs to. The shop gets exactly one customer a month.

That customer is Kurahashi.

Kurahashi is a man well past eighty who lives at the far end of Sidonia Street. Every month, on the second Tuesday without fail, he shows up clutching the same radio. It’s an Earth model, and by his count it’s been forty-eight years.

“Mr. Sano, it stopped on me again.”

He set the radio down on the counter with both hands — the careful way you hand a sick child to a doctor.

Sano popped the back panel and sighed. The batteries were nearly dead again. This model number had been discontinued on Earth years ago. There was no getting them on Mars. You could order them, sure, but three months each way — and by the time they arrived, the spec would have changed.

“Mr. Kurahashi, I told you last month too, these batteries don’t exist anywhere in the solar system anymore——”

“As long as I can hear it.”

He always says that. For the record, FM broadcasting on Mars runs three days a week. One station. It plays nothing but old Earth songs registered during the early settlement period.

Sano sighed and started the same life-extension ritual as last month. First, volume all the way down — you had to press your ear to the speaker, but Kurahashi didn’t mind. Then he cut one of the two speakers. Stereo became mono. Kurahashi didn’t mind that either.

Three months back, Sano had locked it to a single frequency band. There was only one station anyway.

“The only thing left I can do is kill the clock display——”

“Go ahead.”

Sano worked a tiny screwdriver into the clock’s wiring and disconnected it. The LCD went dark. That ought to buy another two months, maybe.

“Thank you, Mr. Sano. See you next month.”

Kurahashi tucked the radio under his arm and started for the door. Sano heard himself say it before he meant to.

“Mr. Kurahashi, I’ve been thinking about closing up, actually.”

Kurahashi turned around and smiled, warm and unhurried.

“Is that so. Well, I’ll still come by next month.”

Sano watched him go with an expression he couldn’t quite name. Though it didn’t really matter — Kurahashi was his last regular, and you don’t turn away your last regular.

The following month. Kurahashi arrived with the radio again. This time, no sound at all.

Sano opened the back. The batteries were completely dead. Nothing left to squeeze.

“Mr. Kurahashi, I’m afraid this time it’s——”

Kurahashi reached into his pocket and pulled something out. A small button cell.

“It’s from my hearing aid. I think the size is close. Would you give it a try?”

Sano held the button cell up next to the battery compartment and compared them. Not quite the same size. But if he wrapped some aluminum foil around it — actually, it might fit.

“Mr. Kurahashi, isn’t this the one that’s in your hearing aid right now?”

“As long as I can hear it.”

He said it again. Sano opened his mouth to say something, then let it go.

He wrapped the foil, pressed the button cell in, and flipped the switch. A wash of noise, and then — faint, a little crackled — an old song drifted through the shop.

Kurahashi closed his eyes and listened. Sano asked, “The volume okay? It’s pretty low.” No answer. The hearing aid battery was inside the radio now.

Sano forgot, again, to flip the CLOSED sign on the door.