He tries the light switch, without luck. So they both click on the headlamps stationed in the visors of their hoods. She steps into the room and the floor feels slippery and loamy beneath her booties’ cloth tread. It is hard to know where to look, so she focuses first on the air—thick with spores highlighted by the beam of her headlamp. She waves a hand and watches the spores swirl in its wake.

She’s reminded of a long-ago investigation into the death of a beekeeper. His hives had been overturned and his body lay among them, so she had to wear a beekeeper’s suit when visiting the scene. The sense of protection it gave her was a delight as the honeybees buzzed and crawled across her body, their stingers so close. She feels something similar now with the spores snowing the air around her.

“Look at these formations,” he says, crouching down to study what looks like an oversize gray cauliflower, one of many knuckling the floor, counters, and walls. When he takes a kitchen knife and pokes at it, a mucusy strand clings to the blade. Then the fruit of the fungus begins to pulse, almost as if it had a heartbeat. He leans in and Nora says, “I wouldn’t do that.” Before he can respond, it ruptures and spits a black cloud of spores into his face.

He falls back on his rear and wipes a hand across his mask. A sooty blackness has coated the plastic and it smears beneath his gloved fingers. “I don’t know whether to say cool or gross,” he says.

“Let’s hurry.”

“The jars were on the island counter,” he says, but this isn’t going to be as simple as snatching them and hurrying off. The fungus has grown thickly over every surface. There are fruiting bulges and hyphae strands. There are gray fibrous striations that look like muscle tissue or the twisted grain of an old tree. Finding anything in this room will require slicing and digging. An autopsy.

“I’ll keep looking,” he says. “You start filling up containers.”

The gloves are clumsy and she has some trouble fingering off the lids of the jars and scooping gloppy samples into them. She tries to be as methodical as possible, taking different excisions from different formations in different parts of the room. There is a mass she pauses over, like a small hill on the floor. Its texture is that of many sticky spiderwebs woven together. She takes the knife and thrusts it into the fungus. She tries to saw it back and forth, but the blade resists. She pauses then, noticing a sudden redness along the metal. She pulls the knife out, and what is unmistakably blood begins to seep from the gash.

“Jack,” she says.

His back is to her as he digs busily at the formation on the counter. “Hold on.”