Isabel waited impatiently with the crowd outside the emergency room. Every time it looked as if she might be able to worm her way inside, another group of people would come running up with a desperately ill friend or relative, and she would have to step aside and let them in. She didn't mind, of course. But she was growing more and more worried by the minute. What was going on here? All these sick people… they seemed to have nothing in common except that they were sick.

So far she'd seen one elderly woman who had an ugly rash all over her arms. A little boy with uncontrollable hiccups. A middle-aged guy whose entire body was shaking violently in a seizure. The latest one carried by had been a girl around her own age who had been vomiting and was completely dehydrated.

What's wrong with Liz? Isabel wondered. Max had called almost an hour ago to tell her he was bringing Liz to the ER. Of course Isabel had rushed right over, but she hadn't been expecting some sort of epidemic.

There was a brief lull in the incoming patients. The area in front of the door was empty. Isabel pushed past the two security guys standing in front of her and sped through the door. One of them called after her, but she kept going as if she hadn't heard him.

Inside, the waiting area was pandemonium. She scanned the room, searching for Max or Liz. Not a sign of them. But, much to her astonishment, she spotted Valenti sitting on a bench next to Maria. Maria's mother was with her, breathing from an oxygen mask.

What on Earth is going on here? Isabel made her way over to them. "Hey," she said. "What's happening? Are you okay, Ms. DeLuca?"

Maria's mom shrugged and gestured to the mask with her hand.

"She's having a severe asthma attack," Maria explained. "Which is bizarre, because she hasn't had asthma since she was seven."

"What caused it?" Isabel asked, taking a seat next to Amy.

"Nothing she can think of," Maria said. "That's why we're worried."

Isabel glanced up at Valenti. She knew he and Maria's mom dated sometimes. Was he here for Amy? Or someone else?

Valenti met her eye and nodded grimly. "Kyle's here too," he told her.

Isabel gasped. She and Kyle had been hanging out a lot lately, and she'd grown attached to him. "What's wrong with him?"

"They don't know," Valenti said, his voice tight with

worry. "He passed out at home, and he's been in and out of consciousness ever since. They want me to wait out here until they run some tests."

Isabel frowned. "Does this seem strange to you guys?" she asked. "Ms. DeLuca getting sick, and Kyle, and Liz?"

"Liz?" Maria repeated. "What's wrong with Liz?"

"Don't you know?" Isabel asked. "Max brought her in here about an hour ago."

"Liz was with Max?" Maria looked surprised.

Valenti shook his head. "We haven't seen either of them."

"Hush," Maria said, nodding toward two nurses who were hurrying across the waiting room. Isabel listened to the nurses' conversation as they passed.

"… everything from acne to symptoms of ALS," one of them was saying. "I've never seen anything like it."

Then the nurses were gone. Isabel glanced up at Valenti and spoke in a low voice. "It seems like everyone's getting sick at the same time. Do you think it's like that green skin thing… something in the water?" Isabel asked, referring to an incident a few months ago. She knew Valenti would understand what she was really asking… did he think this was an alien-threat of some sort?

Valenti's brow was furrowed in thought. "I don't see how it could be," he replied. "Looking around, I see people with all kinds of different symptoms. Amy's having an asthma attack, but that's not what happened to Kyle. And check out that guy."

Isabel followed his gaze to a young man sitting in a corner between two people who were obviously his parents. The guy was talking loudly to himself, every so often swatting the

air in front of him. His mother was in tears, and his father stared silently at the ground.

"Schizophrenia, if I'm not mistaken," Valenti went on. "Meanwhile, the woman over there was complaining that her eyesight suddenly started to go."

"And you don't think one thing could be causing all these different symptoms?" Isabel asked.

"I can't think of anything… anything… that could cause such disparate symptoms," he said with a significant look.

Isabel sighed in relief. Whenever something strange happened, she automatically felt responsible, as if the aliens must have caused it. And usually she was right. But maybe this time was different.

"Help me!" a woman's voice cut through the noise of the ER. "My son's having a heart attack!"

Isabel turned to look along with everyone else.

Several nurses were rushing a stretcher through the doors of the ER. And on the stretcher lay Jesse, his skin pale and his eyes wide and frightened. Isabel was on her feet before she even realized it.

They were pushing the gurney through the room at top speed, Jesse's terrified mother keeping pace with it.

Isabel stepped forward as they passed her, willing Jesse to look at her. Almost as if he could feel the weight of her concern, he turned his head ever so slightly and met her eyes.

"Jesse," Isabel whispered.

And then he was gone, disappearing through a set of double doors into a hospital hallway. Everything inside Isabel cried out for her to follow him, to comfort him and make sure he was okay… and if he wasn't, to find Max and make him heal Jesse.

But he's not even my boyfriend, Isabel thought sadly. Jesse had broken up with her. She had no right to be at his bedside.

"Isabel? You okay?" Maria's voice broke into her thoughts.

Isabel pasted a smile on her face and turned around. "Sure," she said, sitting back down. "I'm fine."

"Let me get this straight," Maris said. "You put the serum in a water bottle. You watched Liz Parker take exactly two little sips of it. And then you sent her home… with the water bottle."

"I didn't know she would share it with anyone else," Alan Sosa said defensively. "It's unsanitary."

"Have you ever met a sanitary teenager?" Maris snapped.

"This isn't my fault," Alan insisted. "You're the one who had me develop the serum. You're the one who told me to give it to Liz Parker. I'm not going to take the blame for this."

"No, Meta-chem will be blamed for it, you idiot!" Maris slammed her hand down on her desk. "Alan, do you even realize what you've done?" she cried. "There is an entire city full of people out there who have ingested nonhuman, possibly nonterrestrial, DNA. They're calling it a virus! Apparently this stuff can reproduce and spread!"

"Well, how was I supposed to know that?" Alan cried. "We never tested it before. Besides, it's not really reproducing. It's not a true virus. The Healer's DNA just seems to attach itself to human DNA. And it doesn't spread like a bacteria."

"I don't care if it lays eggs," Maris cried. "It's hopping from one person to the next, and they're all getting sick. How can they be sick from the Healer's DNA?"

"I told you we don't know how he heals," Alan said. "His DNA attaches itself to the patient's DNA strands. But maybe he does something else while he's healing them."

Maris dropped her head into her hands. This was a disaster.

"There's clearly some link to his healing properties," Alan said. "Because his DNA is certainly affecting people's health."

"Exactly opposite of how we want it to affect their health," Maris said.

Alan turned toward her office door. "You wanted a test, Maris. This is it. This is what the serum does to humans."

His self-satisfied tone brought Maris back to her senses. She sat up and snatched her phone.

"What are you doing?" Alan asked.

"Damage control," she told him. "You're right, this is my test. And I'm going to get the results. I'll see how it affects every single person who's been exposed to it."