I pretend to be grieving because that’s what people do at funerals, right? They knuckle fake tears from their eyes while secretly checking their watches to see if it’s time to go. A magpie cackles from the roof of the crematorium, and I’m surrounded by a half circle of somber-faced mourners offering condolences, hugs and tissues. I think the passing of my mother-in-law should be a cause for celebration. Never again will she put the cutlery back in the wrong trays or forget to refill the water jug after she’s used it to top up the kettle.

I can’t say I’ll miss her.

On the other side of the carpark, my wife talks to a man I don’t recognize. He’s a little taller than her, with greying hair and a look that says, ‘If I concentrate hard enough, I might live forever.’ It’s a look I’ve seen before in the vineyards and auberges of rural France. My mother-in-law spent her teenage years in Provence, so maybe he’s an old friend. He pulls a box the size of a human skull out of nowhere and holds it up for my wife to see. When she touches it, the magpie flies from the crematorium roof.

Two weeks later, our savings account is empty. Ignoring the speed limit on the way home, I phone the bank and navigate the automated queues until I arrive at the hold music. “All our operators are busy at the moment,” says the pre-recorded voice. I pull onto our drive and nearly hit the Frenchman as he leaves our house. We make eye contact, but he doesn’t slow down.

The wooden box is on the kitchen worktop. Walnut with brass fittings. My wife stands over it, serene to the point of glowing.

“Someone’s spent our savings,” I say.

She smiles distantly as though theft is of no interest to her. “My mum,” she says.

“Your mum spent our money?”

“My mum has been returned to me.”

“Her ashes?”

“Her spirit.” She touches the box. “It’s called a Boîte Fantôme.”

“Your mum was a big woman. I don’t think she’d fit in there.”

“Silly,” says my wife. “Her body was big but we burned that.”

“And now she’s in the box?”

“It was worth every penny.”

The Frenchman is a fraud. He’s sold my wife a substitute mother for the sum of our savings. I try to reason with her. I tell her she needs to get our money back. I want her to open the box, so she can see it’s empty.

“Silly,” she says. “If I open the box, Mum will escape.”

I cancel our holiday, because we don’t have the money to pay for it anymore. When the tumble dryer dies, we can’t afford a new one. My wife doesn’t care. Everywhere she goes, she carries the box with her. She empties the contents of her handbag until it sort-of fits. At night, she keeps it on her bedside table. The one time we try to have sex, I can’t relax. I can feel the box watching me.

That’s when I decide to call Shaun.

I blame a lot of things on the fact I married too young. The crappy job I never quit. My unfulfilled desire to backpack around the world. And Shaun.

Shaun and I had been dating for three months when my mother-in-law saw us together. We were leaving a hotel, holding hands. When she asked me about it, my fumbled lie might as well have been a full confession. I sat in my car, inventing excuses, certain she was going to tell my wife, but I needn’t have bothered. The following afternoon, my mother-in-law collapsed on the steps of her church and never regained consciousness.

In bed, Shaun rolls over to ask me about the Boîte Fantôme. I tell him about my mother-in-law’s funeral and how the Frenchman exploited my wife. “You have to open the box,” he says. “You need to set your mother-in-law free.”

I can’t believe he thinks she’s in there — he’s as bad my wife — but he makes a good point. Whether she’s in there or not, opening the box is the right thing to do.

I wait until my wife is in the shower and then search the house. The box isn’t on her bedside table. It isn’t in her handbag. It isn’t on the stacking tables opposite the television. Maybe she’s come to her senses and seen it for what it is. No magic, no ghosts, just a wooden box designed to separate the grieving from their cash. I search every room in the house until there’s only one left.

My wife is singing in the shower as I press open the bathroom door. The Boîte Fantôme is on the toilet. I sneak in and hope the steam on the shower doors will hide me.

“What are you doing?”

Before she can stop me, I seize the box and lift the lid. There’s no sound, no movement, just an empty box and a wife who wants to kill me.

The following morning, I wake up in the spare room and creak downstairs to make a cup of tea. The kettle is empty and so is the water jug. I step back, confused because I’m sure I filled the jug before I went to bed. I check the cutlery drawer and there are knives where there should be spoons; forks where there should be knives.

Someone wants me to think my mother-in-law has come back.

I hear voices in the main bedroom. My wife and somebody else. I race upstairs and barge through the door, expecting to find my wife with her conspirator, laughing at the trick they’ve played on me. But my wife’s alone.

“Who were you talking to?” I ask.

She stares at me, shaking, her eyes brimming with sorrow. “My mum,” she says. “My mum was here.”

And I know what’s coming. I can hear the question before it reaches my wife’s lips.

“Who’s Shaun?”

Christopher Stanley lives on a hill in England with three sons who share a birthday but aren’t triplets. His stories have been published in The Molotov Cocktail, Aphotic Realm and Calendark: The Infernal Almanac, along with many others. Follow him on Twitter @allthosestrings.