As they entered the museum, they were greeted by the sounds of a string quartet. The VIPs in tuxedos and evening gowns were milling about, accepting hors d'oeuvre and drinks from waiters. Amita glanced down self-consciously at her clothes. Charlie noticed her discomfort and wrapped his arm around her shoulders. "You're still the most beautiful woman here," he whispered. "Would you like a drink?"

"Please," she said nervously.

Charlie snared a glass of white wine from a passing waiter and handed it to her. He glanced around, and seeing Ben and Maggie, led Amita toward them.

"Ben," he said, "what do we do now? Just mingle with the 'other half?'"

"For now," Ben said. "After about half an hour, someone, probably the director of the museum, will give a little talk, we'll applaud politely, the wealthy will pull out their wallets, and then they'll let us into the galleries."

Maggie leaned close to Charlie and Amita. "Most of the people you see dressed to the nines wouldn't know a Rembrandt from a Norman Rockwell."

"I beg to differ, my dear," Ben said, "Perhaps they wouldn't recognize the difference in style, but they will know the difference in their portfolios."

"True," Maggie replied, grinning. "And we all know that for some people, the bottom line is the bottom line."

"Now they," Ben glanced at a mixed group of professors in baggy tweeds and students in jeans, "are the ones who really know what's going on. Shall we go mill about in their vicinity?"

The professors were debating the usage of the term "Old Masters," and the students appeared to be running out of patience. A young man glanced at his watch. "Come on. Enough of the booze, fish eggs on crackers and boring music. We came here to see the exhibit, not the politicos."

Charlie glanced around the lobby, and caught sight of Alan, Don and Liz engaged in an intense conversation, eating said fish eggs and drinking said booze. His eyes widened in amazement as he caught sight of a familiar figure, bearing down on Alan like a battleship steaming through the waves. He nudged Amita. "Millie's here."

"You're kidding!" Amita followed his gaze and giggled. "You're not kidding. She must have smelled the wealthy donors all the way from Cal Sci."

Maggie said, "It doesn't look like she has her sights on donors at the moment. I think she's zeroing in on your father."

Charlie sighed. "I'm actually starting to get used to the idea of the two of them together."

"True," Amita said, "but I have yet to hear you use the word 'stepmother.'"

"Baby steps, Amita. Baby steps," Charlie said with a grin. He accepted a beer from a passing waiter. "Looks like I'd better get started," he said, hoisting his beer, "they're heading this way."

"Well," Ben said, "I happen to like Millie."

"Oh," Amita said, "Charlie likes her too. He's just having a hard time seeing her as a mother figure."

Ben chuckled. "I'll admit that motherly is the last adjective I'd apply to our Dr. Finch."

"Good evening, professors!" Millie's voice carried through the lobby. The tweedy professors stopped debating for a moment. When they realized Millie wasn't addressing them, they went back to their argument. "What a surprise! I expected to see Ben and Maggie, and possibly even Alan, but I never expected to see the rest of you. Especially our cute pair of g-men. Or is Liz a g-lady?" She nodded toward Don and Liz. She clapped her hand over her mouth, and with wide eyes, stage-whispered, "Oh no! Have I blown your cover?"

Charlie rolled his eyes and sighed. "No, Mildred. Ben and Maggie had tickets and invited us. There's no reason mathematicians and civil servants shouldn't go to a museum occasionally. I mean, you're here, aren't you?"

"Very true, professor."

"So," Amita said, "what brings you here tonight? Are you a fan of Old Masters?"

Millie lowered her voice. "Actually, I'm a fan of the newer masters – the wealthy donors looking for a nice tax deduction. This is one of their natural habitats." Her eyes lit on a gray-haired couple. "I'll see you later. I need to say hello to some dear friends."

After she left, Charlie chewed his lip nervously. "I'll be right back. I need to talk to Don."

Alan was amusing Liz with tales of Don's misdeeds as a child. Charlie tugged at Don's arm and whispered in his ear. "We need to talk."

Don gave Charlie a confused glance, then said to Liz and Alan, "I'll be right back. Charlie thinks I forgot to lock the car doors."

Don let Charlie lead him out the front door. "What's up, Buddy?"

"I don't know if it makes a difference, but Millie very loudly identified you and Liz as 'g-men.'"

Don pondered for a moment. "I think it'll be okay. There's no law against feds going to a nice reception. We'll just enjoy the art tonight, and discuss our conclusions after we leave. I'll let Liz and Dad know."

Charlie nodded. "I'll tell the others. I just don't want to mess things up. I think Dad's got me second guessing everything."

"Don't second guess yourself." Don chuckled. "Just use the force, Luke."

Charlie laughed. "Okay, Chewie. Let's get back inside. I need to grab one of those bacon wrapped scallops."

Don opened the door and let Charlie in ahead of him. "Only one? I've had half a dozen already."

"I'll start with one. It's a good thing we don't keep kosher."

"You got that right, Buddy," Don said, watching the circulating waiters, trying to find more scallops. "There!" He led the way to a waiter carrying a tray of bacon wrapped scallops on small plates. They each took a plate, thanked the waiter, and headed off in search of their companions.

Liz and Alan had drifted over to talk with Amita, Ben and Maggie. Charlie could hear Millie's voice in the distance. He looked around until he saw her, chatting with the gray haired couple she had spotted earlier. When he looked back, all but one of his scallops were gone, and the other three professors were chewing contentedly. He grinned wryly as he picked up the last scallop. "Would anybody like more?"

At that moment, the music stopped, and one of the tuxedoed gentlemen tapped on a microphone. "Ladies and gentlemen, may I have your attention?"

The murmuring slowly quieted, and the man at the microphone continued, "I would like to thank you all for coming this evening. My name is W. Jennings Stevenson, and I have the honor of directing this lovely museum. And tonight, it is my pleasure to share our most ambitious exhibition to date with you. After years of planning, we joined forces with some of the greatest museums in the world to assemble a traveling exhibit of Old Master drawings and prints. In a few minutes, you will be able to see 'up close and personal,' works by DaVinci, Raphael, Michelangelo, Durer, Rembrandt, and countless others. But, first, let me take a few moments and thank a few of our more generous donors..."

Charlie nudged Amita and whispered,"I can't believe he said 'countless others.' Of course you can count them..."

"Shhhh!" One of the nearby tweed-clad professors hissed.

Charlie narrowed his eyes at the professor, but decided not to belabor the point. Instead, he started scanning the crowd, looking for another trayful of the elusive scallops. Apparently, once the talking started, the eating was supposed to end. He sighed, and turned his attention back to W. Jennings Stevenson. The man was blathering on about donors, and Charlie amused himself by trying to remember if he'd ever heard a more pretentious name.

"..and now, let us go back to the days of the Old Masters." W. Jennings Stevenson stepped away from the microphone, and led the way to the gallery. The group of students tried to maneuver their way to the front of the line, but they were effectively blocked by museum staff. Somehow, the people who looked like they had made the largest donations ended up entering the gallery on the director's heels.

As their part of the crowd slowly crept toward the gallery, Don tapped Charlie on the shoulder. Charlie turned, opening his mouth to ask what Don wanted. Before he could speak, a bacon wrapped scallop miraculously appeared in his mouth.. "Enjoy. I was getting full anyway," Don said, pulling the empty toothpick back.

"Thanks," Charlie mumbled as he chewed.

"That's okay," Don said. "I noticed the sharks wiped out your scallops." He paused. "Do sharks eat scallops?"

"No idea," Charlie said, shrugging. "Too bad Larry's still in space. I'm sure he'd be able to tell you. In great detail."

"No, thanks."

They entered the first room of the exhibit. There was hardly an inch to spare in the place. "How are we going to see anything?" Liz asked,

"Follow me," Ben said, leading them through to the next room, and the room after that, until they reached a room occupied by only half a dozen viewers. "There. We're far from the madding crowds. We'll work our way to the end and by the time we double back, the rooms at the beginning will be emptying out."

"Very clever," Alan said. "I'll have to remember that little trick."

Maggie said, "It works every time there's a limited crowd. Tonight, we have a relatively small group, so the gallery isn't filled with a continuing flow of people. It also works on those timed entry shows."

"The ones where they let a group in every twenty minutes?" Alan asked.

"Right," Ben said. "They let a relatively small group in, and then stop the flow. The group is small enough that it doesn't completely fill the rooms. So, if they have allowed sufficient time between groups, the group will leave the first rooms before the next group is admitted."

"That makes sense," Charlie said. "It's an interesting dynamic. I could design an algorithm..."

"Charlie," Amita said, "your eyes are starting to glaze over. You're visualizing this as some kind of fluid dynamics problem, aren't you?"

"Okay, you got me." With difficulty, Charlie turned his mind from the images of flowing museum visitors and got back to the problem at hand. He glanced around the gallery. "So, Professors Cole, educate me on the fine art of fine art."

By the time they moved on to the next room, Charlie could tell a print from a drawing, and decided he really liked the effect of silverpoint. They had found the Durer and the Michelangelo. As they entered the last room, Ben gasped. "There it is," he whispered.

"What?" Alan asked.

"The Da Vinci. It's a preliminary sketch for a painting he did called 'The Adoration of the Magi.' This is only the second time the Uffizi has allowed this drawing to be exhibited in the United States. Security has always been a concern."

Don took a deep breath and blew it out slowly. "This might just be what we're looking for."

The drawing was small – a little over six inches high by close to twelve inches wide. The background was a light brown. The lines appeared to be a brown ink, along with a few marks that looked like silverpoint. In a few places, a white lead paint had been used to add highlights.

"It's beautiful," Liz said softly. "It's hard to believe this is just a sketch."

Ben said, "This was actually the layout of the background. All of these lines radiating from this point are establishing the perspective for the whole painting." He glanced at Charlie. "And this point was established mathematically. Leonardo called it the divine proportion."

Charlie nodded. "We call it the golden ratio. 'a+b is to a as a is to b.'"

Liz shook her head. "I have no clue what that means. I just know that's one nice looking drawing."

"Well, Liz, if you consider the distance from the viewpoint..." Charlie began, but stopped when he saw Liz's panicked expression. "Never mind. Just enjoy the pretty pictures."

"That's what I plan on doing, professor." Liz grinned. "I'll let you look at it your way. You let me look at it my way." She turned to Ben. "It's an amazing sketch, but it is just a sketch. Why is it so valuable?"

"I believe your initial reaction is a key to its value. You were overwhelmed that so much beauty, so much skill, could be contained in what was to Leonardo a quick sketch. Then there's the opportunity to get a glimpse of the inner workings of Leonardo's mind. To us, the concept of perspective is something beginning art students understand. In Leonardo's day, perspective was a radical concept."

Maggie added, "It's definitely not the rarity that makes it valuable. Unlike Michelangelo, Leonardo did not destroy his notebooks and sketches. We have roughly seven thousand pages of Leonardo's notes."

"So what is it?" Alan asked.

Ben shrugged. "He was a genius."

Don grinned at Charlie. "I"m going to start saving your scrap paper then, Buddy."

"Granted, Charlie is a genius, and some day his notes on his mathematical discoveries will be worth a fortune," Ben said. "However, Leonardo was a genius in almost every field. The thought that one brain could contain so much information is mind boggling."

Amita studied the drawing for a few minutes. "It's called 'Adoration of the Magi.' Where are the magi?"

"He used this sketch to establish the background. This empty spot near the center is where Mary and Jesus would be sitting, surrounded by the crowd worshiping them. Sadly, Leonardo never finished the painting he was commissioned to do. He did quite a few sketches, and began working on the wooden panel, but he left Florence and moved to Milan. The monks eventually hired another artist to paint their altar piece for them. Leonardo's unfinished panel is in the Uffizi in Florence."

The crowd had begun to catch up to them, and they reluctantly moved away from the DaVinci and started to look at the other drawings. Millie entered with a local politician and his wife. When she saw Alan, she excused herself and joined him. "How are you enjoying the show?" She asked as she took his arm.

"It's absolutely beautiful! Have you seen the DaVinci yet?" he asked as he led her back toward the drawing.

"No, I haven't. Is this connected to those thefts..."

"No!" Alan said, cutting her off abruptly. "We are just here to see the Old Masters. Ben and Maggie invited us as a kind of thank you for our hospitality while they've been in Pasadena." He gave Millie a look, and, amazingly, she realized what he was trying to tell her.

"Well, that's very nice of them. They're such a sweet couple, aren't they? They've awakened out faculty and our students to the fact that art and science are very strongly interrelated."

"And speaking of the marriage of art and science, would you look at this wonderful DaVinci drawing? Ben was explaining DaVinci's use of the golden mean."

"Golden ratio," Millie corrected him. "I imagine Charlie was thrilled to hear that."

--

As Alan led Millie away, Don sighed, glancing surreptitiously around to see the reactions of the other visitors. A group of students were giggling as they watched Alan dragging Millie away, but everybody else seemed to be paying more attention to the art. Don turned Liz to look at a nearby print. He leaned close and whispered, "You think she blew it for us?"

Liz shook her head. "I don't think anyone noticed." She added, a little bit louder, "This one looks a lot like the Durer we saw earlier."

"I think you're right." Don checked his watch. "This is going to be over soon. Why don't we go have a look at the rooms we skipped on the way in?"

A few minutes later, they were joined by Ben and Maggie. Charlie and Amita lagged a room behind, keeping an eye out for Alan and Millie.

Once the show was over, Don led the way back to his SUV. While he was unlocking the doors, Millie approached him. "Don, I am so sorry. Alan explained what was going on back there. I didn't really think you were investigating anything, or I wouldn't have joked about it."

"That's okay. I don't think it'll cause any problems."

Millie sighed. "I've just got to learn to keep my big mouth shut." Catching sight of Charlie preparing to say something, she said, "Watch it, Professor. I'm still your boss."

Alan chuckled. "Once you learn, why don't you teach Charlie? Say, Millie, we're heading back to my... uh... Charlie's house. Would you care to join us?"

Millie glanced tentatively at the others, smiling when Don said, "I think that's a good idea. As long as we don't play poker."

--

Alan rode back with Millie. They arrived a few minutes after the others. Charlie was bringing in a bowl of popcorn, and had already served drinks when Alan and Millie walked into the house. Charlie grinned at them. "What took you two so long?"

Alan hung up his jacket, and took Millie's coat. "Millie doesn't speed like some people."

"Hey," Don said from the living room. "I don't speed. I just know how to handle traffic better than you two do."

Millie raised her eyebrows at Don. "And I don't have a siren and flashing light on my car."

Liz laughed. "Oh, he didn't use the lights and siren. I would have had to arrest him if he had. Of course, from where I was sitting, I couldn't see the speedometer, so I can't vouch for him in that department."

"So, Don," Millie said, "I really am sorry if I caused any problems at the museum."

"I honestly don't think you did. If I'd known you were going to be there, I would have filled you in on what we're doing. Have a seat and I'll catch you up. We can always use another analytical mind."

When Millie and Alan had gotten settled, Don began, "Our band of professors here determined that the show at the Armand Hammer Museum was the most likely to be hit by the robbers. And they determined that three of the items in the show were the most likely targets: a Durer print, a Michelangelo drawing, and the Da Vinci drawing."

"My money's on the Da Vinci," Millie said.

Liz glanced at Charlie. "And she did that without a computer. I'm thinking it'll be cheaper for Don to hire Millie as a consultant."

"But our program..." Charlie began.

"I'm kidding, Charlie," Liz said. "I've gotta stop doing this. You're way too easy a target."

Charlie nodded, staring off into space for a moment, then turned to Maggie. "The Da Vinci is a pretty obvious target. But is it an easy target? What did you see as far as security was concerned?"

"Well, it's never good to make security too obvious, but I did recognize a couple of things. There's a motion detector hanging over it, made to look like a spotlight. If you step within the range of the detector, it'll make a chirping sound to warn you, and send a signal to the guards. I tried to get a look at how it was fastened, but I couldn't do it without attracting attention. I doubt if it's just hanging from a hook. The frame is probably bolted to the wall somehow. There's probably a motion detector attached to the frame as well."

"Right," Ben nodded. "And I imagine there will be at least one guard whose sole function is to watch the Leonardo without being obvious about it."

"All right," Don said, "so our thieves like a challenge. This one sounds right up their alley. How is the drawing mounted in the frame? Could a thief pull the frame apart?"

Maggie glanced at Ben. "What do you think?"

"It's possible. I didn't notice any hardware on the frame, so it's possible it could be pulled apart. And the glass is most likely Plexiglas, so there's no danger of the glass shattering and damaging the drawing. Are you planning on contacting the museum?"

Don nodded. "Yeah. I'm seeing the director tomorrow. I just wanted to know what I was talking about before I saw him."

"Would you like us to come with you?" Ben asked.

"I don't think that will be necessary," Don said. "Do you think they'll be likely to strike on opening day?"

"No idea," Maggie said. "According to Ticketmaster, this week and next week are already sold out, so the size of the crowds should be about the same. If they want media attention, opening day would be the best. I imagine every local TV station will have a live feed, unless something more exciting happens."

"So we'll assume they're going to show up on opening day. It can't hurt."

Alan said, "And you're going to have your people there until they make their move?"

"We're going to have to," Don said. "We also can't dismiss the possibility that they're going to hit another museum."

"You're going to be spread pretty thin if they don't act quickly."

"You got that right," Don said, taking a long sip of beer. "I am not looking forward to facing the bean counters on this one. I'm either gonna be the hero or the goat on this one."

"Baaah," Charlie said, grinning.

"Hey, if you're wrong on this one, it's coming out of your fee. Didn't you read the small print?"