Huygens fought panic while Nirin led him through the drizzly twilight street, which was guarded by twice as many sentries as usual. On the mainland, he saw red banners in the hills. Japan and his country must indeed be at war. Silently Huygens rehearsed the statements he must convince Sano to believe: I didn’t kill Jan Spaen. I know nothing about any smuggling. I’m not the enemy; I’m innocent!

They reached the surgery. Lamps burned in the windows. Nirin opened the door and shoved Huygens inside, ordering, “Save him, barbarian!”

Instead of Investigator Sano, four guards and a scared-looking junior interpreter occupied the room. Huygens experienced a rush of relief. Then he saw, lying on the table, the still, blanket-covered body of a young samurai. His face was white, his eyes closed.

Speaking too fast for Huygens to understand, Nirin whipped the blanket off the boy. Huygens’s heart jumped when he saw the deep gash on the naked thigh, still oozing blood despite the tourniquet someone had applied.

“His son,” the interpreter translated. “Hurt when Dutch ship sink barge. Please, honorable doctor, you heal?”

The Deshima staff often defied the rules and came to Dr. Huygens for medical treatment. Now Huygens forgot Jan Spaen, Sano, and the past as his professional self took command. Hurrying over to the youth, he touched the cold neck and felt only a weak pulse.

“Bring hot water,” he said.

The interpreter translated; the guards obeyed. Washing the blood from the injury, Huygens saw that it was deep and serious. A slit artery leaked precious blood into the mangled tissue. Cauterization—the usual method of burning a wound shut with a hot poker—wouldn’t work. From his medical kit, Huygens took a thin needle and a long human hair. Using a technique he’d developed at Leyden University, he sewed the cut artery with tiny stitches. He closed the flesh around it with a thicker needle and a strand of horsetail. The Japanese murmured in awe. Huygens removed the tourniquet, then cleaned and bandaged the wound.

“Your son has lost a lot of blood,” he told Nirin. “To live, he’ll need more. You must bring me a dog.”

Suspicious queries greeted the interpreter’s translation: The men wanted to know if Huygens meant to violate the Dog Protection Edict, their bizarre law that favored animal life over human.

“I don’t have time to explain,” Huygens said impatiently. “Get the dog, or the boy will die.”

The guards ran out the door. Huygens, Nirin, and the interpreter stood around the patient. Glancing from the son’s deathly white face to the father’s grim one, Huygens experienced a thrill of fear. If he failed to repair the damage done by his people, would the Japanese kill him for revenge? Beneath his fear rose the hope of release from a life worse than death. …