Instead of answering, I point down at her crossword puzzle. “Quito,” I say. “That’s the answer to forty-two across.”

She gets all excited and reads aloud the next clue. I think about how happy she’ll be if we finish this crossword puzzle. She’ll get off the plane and tell her son-in-law, or whoever is picking her up, about the nice young man she met. About how helpful I was. How proud my parents must be of me.

My brother is not as smart as I am.

I am not saying this to be mean; I’m just stating a fact. For example, he has to study all his vocabulary words if he wants to do well on a test; I can look at the page and it’s stuck in my head for easy retrieval after that first glance. He would leave the room if two adults started discussing adult things, like current events; I would just pull up a chair and join the conversation. He doesn’t care about storing information away like a squirrel would save nuts for the winter; it’s only interesting to Theo if it has current real-life applications.

However, I am not nearly as intuitive as my brother. This is why when I begin to let some of that stored information bleed free-like for example how Steve Jobs and Steve Wozniak released the Apple I computer on April Fool’s Day 1976-and the person I am speaking with begins to go glassy-eyed and make excuses, I will keep talking, although Theo would easily read the clues and shut up.

Being a detective is all about intuition. Being a good crime scene investigator, however, requires great thoroughness and intelligence. Which is why, while my mother is rendered immobile by her panic over Theo’s disappearance and Oliver is doing stupid things like patting her shoulder, I go to Theo’s bedroom and get on his computer.

I am very good with computers. I once took my guidance counselor’s laptop apart and put it back together, motherboard and all. I could probably configure your wireless network in my sleep. Here is the other reason I like computers: when you are talking to someone online, you don’t have to read expressions on faces or interpret tones of voice. What you see is what you get, and that means I don’t have to try so hard when I interact. There are chat rooms and message boards for Aspies like me, but I don’t frequent them. One of the house rules in the family is to not go to websites my mother has not vetted. When I asked her why, she made me sit down with her and watch a television show about sexual predators. I tried to explain that the website I wanted to chat on wasn’t quite the same thing-that it was only a bunch of people like me trying to connect without all the bullshit that’s part of face-to-face meetings-but she wouldn’t take no for an answer. You don’t know what these people are like, Jacob, she said to me. In fact, I did. It was the people in the real world I didn’t understand.

It takes only a few clicks to delve into his cache-even though he thinks he’s emptied it, nothing is ever really gone on a computer-and to see where he was last surfing the Net. Orbitz.com, flights to San Jose.

When I bring downstairs the printout of the webpage that has his ticket information on it, Oliver is trying to convince my mother to call the police. “I can’t,” she says. “They won’t want to help me.”

“They don’t get to pick and choose their cases-”

“Mom,” I interrupt.

“Jacob, not now,” Oliver says.

“But-”

My mother looks at me and starts crying. I watch one tear make an S-curve down her cheek. “I want to talk to you,” I say.

“I’m getting the phone,” Oliver says. “I’m dialing 911.”

“I know where Theo is,” I tell them.

My mother blinks. “You what?”

“It was on his computer.” I hand her the printed page.

“Oh my God,” my mother says, holding her hand up to her mouth. “He’s going to Henry’s.”

“Who’s Henry?” Oliver asks.

“My father,” I answer. “He walked out on us.”

Oliver takes a step backward and rubs his chin.

“He’s connecting in Chicago,” I add. “His plane leaves in fifteen minutes.”

“You can’t catch him before he takes off,” Oliver says. “Does Henry know? About Jacob?”

“Of course he knows about me. He sends checks every year for my birthday and Christmas.”

“I meant does Henry know about the murder charge?”

My mother looks down at the fault line between the cushions of the couch. “I don’t know. He might have read about it in the papers, but I didn’t talk to him about it,” she admits. “I didn’t know how to tell him.”

Oliver holds out the phone. “Now’s the time to figure that out,” he says.

I don’t like to think of Theo on a plane; I don’t like planes. I understand Bernoulli’s principle, but for the love of God, no matter how physical forces are being exerted on the wings for lift, the hardware weighs a million pounds. For all intents and purposes, it should fall out of the sky.

My mother takes the phone and starts to dial a long-distance number. It sounds like the notes of a game show theme song, but I can’t remember which one.

“Christ,” Oliver says. He looks at me.

I don’t know how I’m supposed to respond. “We’ll always have Paris,” I say.

When Theo was eight, he became convinced that there was a monster living underneath the house. He knew this because he could hear its breath every night when the radiators in his room hissed awake. I was eleven and very into dinosaurs at the time, and as thrilling as it was for me to assume that there might be a sauropod rooting around under the foundations of our house, I knew this was not likely:

1. Our house was built in 1973.

2. To build it, there would have been an excavation.

3. The probability of the world’s sole long-lost dinosaur surviving the excavation and residing beneath my basement floor would be pretty slim.

4. Even if it had survived, what the hell would it be eating?

“Grass clippings,” Theo said, when I told him all this. “Duh.”

One of the reasons I like having Asperger’s is that I don’t have an active imagination. To many-teachers and guidance counselors and shrinks included-this is a great detriment. To me, it’s a blessing. Logical thinking keeps you from wasting time worrying, or hoping. It prevents disappointment. Imagination, on the other hand, only gets you hyped up over things that will never realistically happen.

Like running into a hadrosaur on your way to the bathroom at 3:00 A.M.

Theo spent two weeks freaking out in the middle of the night when he heard the hiss from heating registers in his room. My mother tried everything-from warm milk before bedtime to an illustrated diagram of the heating system of the house to an unnecessary dose of children’s Benadryl at night to knock Theo out-but like clockwork, he’d start screaming in the middle of the night and would run out of his room and wake both of us.

It was getting old, frankly, which is why I did what I did.

After my mother tucked me in, I stayed up with a flashlight hidden under my pillow and read until I knew she had gone to bed, too. Then I took my pillow and blankets and sleeping bag and camped outside Theo’s bedroom door. That night, when he woke up screaming and tried to run to my mother’s room to wake her up, too, he tripped over me.

He blinked for a second, trying to figure out if he was dreaming. “Go back to bed,” I said. “There’s no stupid dinosaur.”

I could tell he didn’t believe me, so I added, “And if there is, he’ll kill me first before he gets to you.”

This actually worked. Theo crawled back into bed, and we both fell asleep again. My mother was the one who found me sprawled on the floor the next morning.

She panicked. Assuming I’d had some kind of seizure, she started shaking me. “Stop, Mom,” I finally said. “I’m fine!”

“What are you doing out here?”