She had done her research at a public library in Novi, before she had even committed to the plan. Gas fireplaces, like the one Tom used, had a small sliding cylinder of steel called a combustion shroud, that could only be adjusted when the flame was off. All Odilie had to do was simply adjust this sliding cylinder, and once Tom turned on the fireplace, the appliance would begin emitting carbon monoxide. The only noticeable difference would be the color of the flames, yellow instead of blue, a change Odilie was certain Tom wouldn’t be observant enough to discern; Odilie believed that he wouldn’t try to leave, that the effects of the gas would hit him before that could become a problem. It wouldn’t take too long for the gas to do its job and because of the room’s sealed nature, with barely a sliver of space under the door, no other part of the house would be affected. The carbon monoxide detector near the bedrooms would be too far away to sense anything, but she removed the batteries just in case.

SNAPea had moved his computer, which was in the home office, because of the board’s new rule about working out of HQ, and only HQ; Tom was waiting for some newfangled laptop to arrive. But surprisingly, this hadn’t deterred him from shutting himself in there the past couple of nights. He told Odilie he was enjoying himself and working on a “tech-free secret project,” a term at which she rolled her eyes.

After adjusting the combustion shroud with latex gloves on—no fingerprints—she ordered in dinner, a falafel pita sandwich. She heard Tom come home, the slam of the front door, the squeak of his shoes as they slid off. She hated that squeak. He poured himself a beverage, made a soft exhale the moment after he took a sip. She didn’t want to engage with him. There was no need. She didn’t have any parting words for him.

She put Penelope to bed, reading her Make Way for Ducklings, and petting her head as she watched her velvety eyes flutter closed. “What do you think of just Mommy and Penny and Baby?” she asked, stroking the bridge of her daughter’s nose, the soft spot just between her eyes. But Penelope was already sound asleep, her breathing heavy and rhythmic.