Cal looked positively haggard. "Do you know how long it will take to check this entire program?" he asked incredulously. "This thing is huge. It's the most complicated program I've ever worked on."

"Maybe a Cray…" she murmured, looking back at the pod.

"Book time on a Cray supercomputer?" Yates made it a question, but he was already mentally running through the logistics. "Expensive as hell."

"Not as expensive as stopping the program."

"It could take forever to get a booking, unless the Pentagon can line up some priority time."

"Yeah, that's a fine idea," Adrian said impatiently, "but you people are forgetting that the big man gave us thirty-six hours, of which we have already used ten. I don't think he's going to be satisfied with a possibility."

"We've come up with nothing everywhere else. Do you have a better idea?" Caroline replied just as impatiently.

He glared at her without answering. The truth was, they had all reached a dead end.

Caroline didn't mention her other conclusion, that if the solution to their problem was in the computer program they still had to discover whether it was a basic error in programming or if someone had deliberately programmed it in, but running everything through a Cray would give them the answer to that. By comparing the working program with the original, the Cray could tell them if the working program had been altered in any way. If it hadn't, then it was back to the drawing board for DataTech; if it had, then they had to find the person responsible for the changes.

"So what do we do?" Cal asked, rubbing his eyes. "Stop looking and just assume we're going to find it in the program, or stay up all night looking for something when we don't know what we're looking for?"

Despite herself, Caroline had to grin. "If you're as groggy as that sentence sounded, I don't think you can stay up all night."

He gave her a bleary look and an equally bleary grin. "Sad, isn't it? In my younger days I could carouse all night and work all day, then go back out for more carousing. What you see here is a shadow of my former self."

"I'm glad you two don't find this serious," Adrian snapped.

"Knock it off!" Yates ordered, temper in his usually calm voice. They were all tired and frazzled. He moderated his tone. "I mean it literally as well as figuratively. We aren't accomplishing anything except exhausting ourselves. We're calling it quits for the night, despite what I said earlier. I think we've eliminated everything it could be except the program, so that's our logical next step, and we can't do it here. I'm going to clean up and have a good meal while I think about this, then I'm going to have a talk with Colonel Mackenzie. Let's get some rest."

Captain Ivan Hodge, head of security, said without preamble, "We have a very suspicious pattern here, sir."

Joe's stem face showed no emotion, though he wished the captain hadn't found anything.

Major General Tuell's flinty eyes became even flintier. As base commander, he was ultimately responsible for everything that happened, and he was intensely concerned with whatever had caused the crash of an F-22. "Show us what you've found."

The captain was carrying a thick log. He deposited it on Joe's desk and flipped it open to a premarked page. "Here." He noted an entry he had already highlighted in yellow. "This is the security code number for a member of the laser team, Caroline Evans. She arrived last Tuesday as a replacement for a worker who had a heart attack."

Joe's guts knotted up and his eyes went blank as he waited for Captain Hodge to continue.

"She has a pattern of arriving in the morning before everyone else and being the last to leave," the captain said, and Joe relaxed a little. Caroline was a workaholic; hardly damning circumstances, and he himself had walked in on her unannounced several times, catching her doing nothing suspicious… although she had quickly cleared the computer screen that one time.

He had briefly wondered about it, then forgotten it, until now.

"You yourself have that pattern, sir," Captain Hodge said to Joe. "In itself, it doesn't mean anything." He flipped to another premarked page. "But here, on Thursday night, the sensors show Ms. Evans entering the laser work area shortly before 2400 and not leaving until almost 0400. She was alone the entire time. She reentered the building at 0600 for her normal workday. The birds went up that morning and for the first time experienced some malfunction with the lasers, isn't that right?"

The ice was back in Joe's eyes. "Yes."

"She left the area late that afternoon with the other members of the team and didn't return until Sunday night, again shortly before 2400. Again, she was the only person there. She left the building at 0430, returned at her usual time of 0600. This time, Major Deale's aircraft was shot down. Hell of a lot more disruptive than the lasers not working at all. These midnight appearances in the work area, combined with the fact that the trouble didn't start until she arrived, don't look good." The captain hesitated as he looked at Joe. The colonel's expression was enough to make any sane man hesitate, and Captain Hodge considered himself very sane. Nevertheless, it had to be said. "I understand you've taken a… uh, personal interest in Ms. Evans."

"We've gone out together a few times." They'd done a hell of a lot more than that, he thought savagely. She had given herself to him with a completeness that had shattered his memories of other women, reduced them to nothingness. And after they had returned from Vegas Sunday night she had slipped out to the work area and… done what? Secretly activated the laser on Bowie's aircraft? Had the laser on the bird he'd been flying been activated, too? Could he just as easily have been the one who shot down a friend?

Captain Hodge looked uncomfortable. "While you were with her, did she say anything? Ask any questions pertaining to Night Wing?"

"No." He was certain of that. Work had been mentioned in only the most general way. But then again, why should she have to ask him anything? "She has the clearance to find out anything about the project that she wants without having to ask anyone else."

"That's true. But did she say anything that, in retrospect, you could construe as being a reason for wanting the lasers to fail? Or for wanting to scuttle the Night Wing project?"

"No." But she wouldn't; Caroline was too smart for that. Caroline was brilliant. Caroline was perfectly capable of activating the lasers; she was not only an expert, she had access to the codes. "She has the knowledge and she had the opportunity," he heard himself saying. "Do you have anything else? Motive, anything suspicious in her past, any current money problems?"

"Her background is clean as a whistle," the captain admitted. "We're going to do a total recheck to make certain it's correct and none of it has been fabricated, but that's only a precaution. Everyone connected with this project has been verified down to the fillings in their teeth."

"Clarify this for me," Major General Tuell said. "She could activate the lasers from the work area, without actually being in contact with the lasers themselves? The birds are under twenty-four-hour guard."

"Yes, sir," Captain Hodge said. "By computer command. And Ms. Evans carried a double major in college. She got her doctorate in physics, but she also has a master's in computer sciences. She knows her way around computers."

"I see." The general sighed. "What are your recommendations?"

"We won't file formal charges, sir. We can prove opportunity, and the timing is very suspicious, but we haven't as yet proven that the computers have actually been reprogrammed to arm and fire the lasers. There's still a possibility that it's a mechanical snafu."

"But you don't think so?"