“And whose fault is that?” I interrupt.

“I’m not going to let my brother die.” Mei straightens the rug. “Cate, you can come with me or stay, it’s up to you, but I’m going.”

“Of course I’m coming with you.” I dart past Inez, but she catches at my arm.

“Heal him if you must, but then erase their memories,” she hisses, her breath hot against my ear.

I tug away without a response. Rilla pushes in her chair and chases after us.

“And where do you suppose you’re going, Miss Stephenson?” Inez barks. “You’ve no affinity for healing at all!”

Rilla gives her an impudent grin, smoothing her chocolate velvet gown. “All this talk of brothers reminded me that I forgot one of mine. I got Christmas gifts for everyone except Jamie, and he’ll never forgive me. I’m such a cabbagehead!”

Inez eyes Rilla’s half-full plate. “And you’re going to remedy that now? In the middle of your supper?”

Rilla points at the clock on the mantel. “The shops will be closing soon, and my train to Vermont is first thing tomorrow. I’ve got to go right now, simply got to, or you can’t imagine the row we’ll have tomorrow night.”

Inez steps aside. Mei runs ahead to get her things, while Rilla and I pause at the far end of the hall. “You got Jamie that book on botany,” I remind her.

“I know.” Rilla holds out her palm. “Give me your necklace. I’m going to see if Merriweather’s at the shop. He ought to come see firsthand what witches and the fever are like.”

• • •

A hired hack is waiting in front of the convent. Mei tells her father that I’m a nurse and she wants me to take a look at Yang. He examines me over half-moon spectacles, and I wonder what he sees. A tall, thin girl with blond hair straggling out of her simple chignon, wisps of it framing her pointy stubborn face, and sad blue eyes? I don’t think I look terribly impressive. But he shrugs and says it couldn’t hurt, and we ride the rest of the way in silence.

The carriage stops at the edge of the market district. Mr. Zhang climbs out and hands Mei and me down. The buildings here push up against narrow, cracked brick sidewalks. This block contains a general goods store on the corner, a milliner, a shoemaker, and—in the middle—a shuttered shop with a simple red sign reading ZHANG’S HABERDASHERY. Upstairs, candles burn in both front windows.

Mei opens the door to the flat and pounds up the stairs. She pauses to hang up her cloak and remove her boots, adding them to the row of shoes lined up beneath the hall table. I follow suit. “Mama?” she calls, weaving through a cozy parlor. It’s cluttered with a mishmash of furniture: two tufted sofas and a battered settee all in bright clashing colors, several ottomans, a wooden chair with pineapples carved into the arms, and a host of small tea tables crowded with empty teacups. A pile of dresses lies next to a sewing basket beneath a lamp with no shade. A doll and several carved wooden animals are scattered across the hooked rugs.

“Mei?” A plump little woman bustles out of another room. She’s wearing a bright orange paisley shawl over a brown dress. “Who’s this?”

“Mama, this is my friend Cate.” I smile as Mei takes her mother’s hands. “How is he?”

Mrs. Zhang’s eyes fill with tears. “Not good. You shouldn’t have come. The fever is very contagious. I’ve sent the little ones to your auntie Yanmei’s until—”

“Until he’s better,” Mr. Zhang interrupts, coming up behind us in his stocking feet. “Can I offer you a cup of tea, Miss Cahill? Jia, Miss Cahill is a nurse.”

Mrs. Zhang pulls away from Mei, dabbing at her eyes with a lace-edged handkerchief. “Is that so? Do you think you could help Yang?”

“I—I hope so.” I clasp my hands nervously behind my back. What if I can’t heal Yang, and he dies anyway, and they’re furious with me for making promises I can’t keep?

“Mama, Baba—there’s something I need to tell you first.” Mei draws her hand, wrapped in mala beads, out of her pocket. “Something I should have told you ages ago. I’m . . . a witch.”

Her parents glance back and forth at each other, and I can’t read them. I hope I won’t need to compel them to forget this.

“Say something, please,” Mei begs.

“We know,” her mother says finally. She reaches up and tucks a wayward strand of black hair, streaked with gray, into her bun. “We’ve known for years, Mei.”

Mei sags onto the violet sofa. “I— How?”

Mr. Zhang puts his hand on Mei’s shoulder. “Quite a lot of strange things happened around here before you went off to that school.”

“I’m sorry it took a situation like this for you to finally tell us.” Mrs. Zhang’s soft voice is full of reproach. “Surely you knew we wouldn’t throw you out on the street?”

“We were so worried when you went away to that school. Proud of your scholarship, of course, but we didn’t know what might happen if you did magic by accident in front of all those devout ladies.” Mr. Zhang peers up at me. “You accept Mei as she is?”

Mei laughs. “Cate’s a witch, too. They’re all witches.”

Her father’s face scrunches into confusion. “Your auntie Yanmei went to the convent school when she was a girl. Before she was married.”

“Who do you think told me they were all witches? She caught me turning Yang’s hair pink while he was sleeping and suggested I learn how to control my magic before I got myself in trouble!” Mei explains.

“Yanmei is a witch?” Mr. Zhang takes off his spectacles and rubs them on the front of his gray vest.

A fit of coughing drifts out of the next room, and Mrs. Zhang darts a worried glance in that direction. “There isn’t any truth to what the Brothers are saying, is there? That the witches set the plague on the people?” She twists her handkerchief in her hands.

“No! We would never do anything like that.” Mei stands. “But healing is a type of magic, and Cate and I are both good at it. Cate’s the best in the whole convent. If anyone can fix Yang, she can.”

I bite my lip. “I might not be able to heal him entirely, though. The fever—it’s rather resistant to magic.”

“Anything you can do,” Mr. Zhang says, wincing at the sound of more coughing. “We’d be very grateful.”

Mrs. Zhang leads us into the small bedroom. She gestures at her son, who’s lying in a small wooden bed with all the covers thrown off. The window is cracked open to let in fresh air, and my teeth are soon chattering, but Yang is flushed, his forehead beaded with sweat, his white nightshirt soaked with it.

His mother holds a glass of water to his lips and he drinks greedily, then coughs again. His breath is labored, rasping. Mrs. Zhang pushes damp black hair off his forehead. “I’ve been giving him ice baths, but he’s still burning up.”

“Let me try.” I move to his bedside with a confidence I don’t feel. “Hello, Yang. Remember me? I’m Mei’s friend Cate.” Yang looks up at me with dull, fevered eyes. His lips are dry and cracked. “It’s all right. Don’t try to talk. Let me just take your pulse.” I pick up his damp hand and put my fingers on his wrist. His pulse is too fast. The second I touch him, I can feel the fever. It burns red in his lungs, coating his airways with infection. I push against it and it seems as though it pushes right back.