Nine-year-old Eli Mercer was halfway across the MRI room when his red backpack ripped him off his feet.

Then the scanner’s speaker crackled.

“Keep coming, Eli. Your mother is inside.”

Dr. Rowan Hale heard the voice from the hallway.

She had been walking back to the emergency department after reviewing a patient’s brain scan when she saw the boy disappear through the open door of MRI Suite Three.

“Eli!”

He either didn’t hear her or didn’t understand the danger.

The imaging department was nearly empty at two in the morning. The lights had been dimmed, and the usual daytime noise had faded to the low hum of ventilation systems and distant floor polishers.

Eli stumbled forward.

The red backpack jerked backward so violently that both straps tightened around his shoulders. He fell onto his knees and screamed.

Something heavy slammed against the inside of the bag.

Rowan stopped at the warning line outside the room.

The MRI scanner had not suddenly become magnetic. The main magnet was always active. Anyone who worked near the suite knew that.

But the safety door was supposed to be locked.

The ferromagnetic detection system was supposed to sound an alarm if anyone carrying a large metal object approached the scanner.

Neither had happened.

Inside the room, the patient table began moving toward the bore.

Lights flashed along the side of the machine.

A mechanical knocking sound exploded through the suite as a scan sequence started.

The noise terrified Eli.

He tried to crawl away, but the backpack dragged him toward the scanner.

“Take it off!” Rowan shouted. “Eli, get your arms out of the straps!”

“I can’t!”

The straps had twisted under his arms.

Rowan looked down at herself.

Her phone was clipped to her waistband. A stethoscope hung around her neck. Trauma shears, keys and a metal badge reel were attached to her scrub pants.

She tore everything off and threw it behind her.

Another contraction tightened across her abdomen.

Rowan froze, one hand pressing against the underside of her belly.

She was thirty-five weeks pregnant. Two days earlier, her obstetrician had warned her that the irregular tightening she had been feeling could become active labor if she did not slow down.

She had promised she would.

Then Eli screamed again.

The backpack slid several inches across the floor.

Rowan crossed the warning line.

“Look at me,” she told him.

Tears covered Eli’s face.

“I came to find my mom.”

“I know. Keep looking at me.”

Rowan moved closer on her hands and knees, keeping her body low. The magnetic pull increased as she approached the scanner.

The object inside the backpack shifted again.

The zipper split open.

A large steel wrench pushed halfway through the torn fabric.

Rowan’s stomach dropped.

If it came free, it could become a projectile.

She crawled toward the emergency panel mounted near the wall.

The scanner’s speaker came to life again.

“Don’t touch that panel.”

The voice had been electronically distorted, but it was clearly coming through the control-room system.

Someone was watching them.

Rowan looked through the glass separating the scanner room from the control area.

The chair was empty.

The computer monitors were on.

The scan sequence had been activated remotely.

Eli was crying so hard he could barely breathe.

“The straps hurt.”

“I’m going to stop it,” Rowan said.

She reached the emergency panel.

The magnet quench button was protected by a clear plastic cover.

Quenching the magnet was not the same as turning off an ordinary machine. It forced the liquid helium cooling system to rapidly release, collapsing the magnetic field.

It could destroy parts of the scanner.

It could cost the hospital hundreds of thousands of dollars.

It could also create a dangerous oxygen problem if the venting system failed.

Rowan lifted the cover.

“Dr. Hale.”

The speaker voice was calmer now.

“Think carefully. That scanner belongs to the hospital.”

Rowan stared at Eli.

The boy was being dragged toward the bore by an object someone had deliberately placed in his backpack.

“The hospital can buy another scanner.”

She struck the button.

An alarm began blaring.

The knocking sequence stopped.

A deep rushing sound moved through the walls as the system began venting helium through the emergency exhaust.

The magnetic field did not disappear instantly.

The wrench pulled harder before the force slowly began to weaken.

The backpack slid another foot.

Rowan threw herself forward and grabbed Eli by the front of his jacket.

Pain ripped through her lower abdomen.

She cried out but did not let go.

“Get your right arm out!”

“I can’t!”

“Yes, you can. Push your elbow back.”

Eli twisted.

One arm slipped free.

The wrench tore completely through the backpack.

It shot across the remaining distance and struck the inside edge of the scanner with a deafening metallic crash.

Rowan covered Eli’s head with her body.

The wrench stayed pinned against the machine as the field continued collapsing.

“Move!” she shouted.

Eli pulled his other arm free.

Rowan dragged him toward the doorway.

They crossed the warning line just as hospital security and two imaging technicians came running down the hall.

Eli rolled onto his side, coughing and sobbing.

Rowan sat against the wall.

Her hands were shaking.

A warm sensation spread beneath her scrubs.

For one frightened second, she thought her water had broken.

Then another contraction began.

This one was stronger than the last.

A technician knelt beside her.

“Dr. Hale, are you hurt?”

“Check the boy first.”

“Eli’s conscious. He’s breathing.”

Rowan looked through the control-room window.

One of the monitors displayed the system log.

The most recent entry was still visible.

REMOTE SCAN SEQUENCE INITIATED.

Below it was another message.

SAFETY DOOR OVERRIDE ACCEPTED.

Someone had unlocked the MRI room.

Someone had disabled the detector.

Someone had used the speaker to guide Eli toward the scanner.

A security guard moved toward the control room.

“Don’t touch the computer,” Rowan said. “Call the police.”

Eli suddenly grabbed her hand.

“My mom is supposed to be here.”

Rowan looked at him.

Eli held up an employee badge.

The photograph belonged to Tessa Mercer, a night-shift nurse in diagnostic imaging.

Rowan knew her.

Everyone did.

Tessa was quiet, careful and almost painfully responsible. She was the kind of nurse who checked a patient’s identity twice even when she had known them for years.

“Where did you get that?” Rowan asked.

“It was taped to the door.”

Eli pointed toward MRI Suite Three.

A folded piece of paper lay on the floor near the entrance.

A technician picked it up with gloved hands.

Four words had been printed in black ink.

YOUR MOTHER IS INSIDE.

Rowan’s next contraction stole her breath.

As the nurses lifted her onto a stretcher, Eli kept holding her hand.

“Please find her,” he whispered.

Rowan looked at the empty scanner.

There had been no one inside it.