Which is missing.

I sink down on his bed and smooth my hand over his pillow. Right now, at 12:45, Jacob is in physics class. He told me this morning that they are doing a lab on Archimedes’ principle, trying to determine the density of two unknown materials. What mass, when inserted into a medium, causes it to displace? What floats, and what sinks?

I will go to the school and pick the boys up, making up an excuse-a dentist’s visit, a haircut appointment. But instead of coming home we will drive and drive until we cross the border into Canada. I will pack suitcases for them, and we will never come back here.

Even as I am thinking this, I know it could never happen. Jacob would not understand the concept of never coming back home. And somewhere, in a police station, Jess’s boyfriend is being blamed when he might be innocent.

Downstairs, with numb fingers, I pick through the stack of bills that I haven’t sorted. I know it’s in here somewhere… and then I find it, beneath the second notice from the phone company. Rich Matson’s business card, with his cell phone number scrawled on the back.

Just in case, he had said.

Just in case you happen to think that your son might be involved in a murder. Just in case you are confronted with the glaring evidence that you have failed as a mother. Just in case you are caught between what you want and what you should do.

Detective Matson has been honest with me; I will be honest with him.

His voice mail picks up immediately after I dial the number. The first time, I hang up, because all of my intended words have become jammed together like putty. The second time, I clear my throat. “This is Emma Hunt,” I say. “I… I really need to speak with you.”

Still holding the phone like an amulet, I wander into the living room again. The news program is over; now there is a soap opera on. I rewind the action until the segment about Jess Ogilvy plays again. I deliberately keep my eyes trained to the other side of the screen, but it’s still there: a flag on the field, a nanosecond of truth in all the shades of the color spectrum.

No matter how hard I try, I can’t unsee that damn quilt.

Jess is dead.

My mother tells me after school. She stares at me when she says it, as if she’s trying to find clues in my expression, the same way I scrutinize the tilt of someone’s eyebrows and the position of their mouth and the size of their pupils and try to connect them with an emotion. For a moment I think, Does she have Asperger’s, too? But then, just when it seems that she is analyzing my features, hers change, and I can’t tell what she’s feeling. Her eyes look tight at the edges, and her mouth is pinched. Is she mad at me, or is she just upset about Jess being dead? Does she want me to react to news I already know? I could act like I’m shocked (jaw dropped, eyes round), but that would also mean I’m lying, and then my lying face (eyes looking up at ceiling, teeth biting down on bottom lip) would do a hostile takeover of my shocked face. Besides, lying is right up there on the House Rules list. To recap:

1. Clean up your own messes.

2. Tell the truth.

Regarding Jess’s death: I have done both.

Imagine what it would be like if you were suddenly dropped from America into England. Suddenly bloody would be a swear word, not a description of a crime scene. Pissed would be not angry but drunk. Dear would mean expensive, not beloved. Potty isn’t a toilet but a state of mind; public school is private school, and fancy is a verb.

If you were dropped into the UK and you happened to be Korean or Portuguese, your confusion would be expected. After all, you don’t speak the language. But if you’re American, technically, you do. So you’re stuck in conversations that make no sense to you, in which you ask people to repeat themselves over and over, in the hope that eventually the unfamiliar words will fall into place.

This is what Asperger’s feels like. I have to work so hard at the things that come naturally to others, because I’m just a tourist here.

And it’s a trip with a one-way ticket.

Here are the things I will remember about Jess:

1. For Christmas she gave me a piece of malachite the exact size and shape of a chicken egg.

2. She is the only person I’ve ever met who was born in Ohio.

3. Her hair looked different indoors than it did outdoors. When the sun was shining, it was less yellow and more like fire.

4. She introduced me to The Princess Bride, which is possibly one of the greatest movies in the history of filmmaking.

5. Her mailbox at UVM was number 5995.

6. She fainted at the sight of blood, but she still came to my presentation this fall in physics about spatter patterns, and she listened with her back to the PowerPoint presentation.

7. Even though there were times when she probably was sick of hearing me talk, she never, ever told me to shut up.

I am the first person to tell you that I do not really understand love. How can you love your new haircut, love your job, and love your girlfriend all at once? Clearly the word doesn’t mean the same thing in different situations, which is why I have never been able to figure it out with logic.

The physical side of love terrifies me, to be honest. When you are already hypersensitive to the feeling of anything against your skin or to people standing close enough to touch you, there is absolutely nothing about a sexual relationship that makes it an experience you look forward to attempting.

I mention all this as a disclaimer to the last thing I will remember about Jess:

8. I could have loved her. Maybe I already did.

If I were going to create a science fiction series on television, it would be about an empath-a person who can naturally read the auras of people’s emotions and, with a single touch, can take on their feelings, too. It would be so easy if I could look at someone who was happy, touch him on the arm, and suddenly fill with the same bubbles of joy that he’s feeling, instead of anguishing over whether I’d misinterpreted his actions and reactions.

Anyone who cries at a movie is a closet empath. What’s happening on that screen bleeds through the celluloid, real enough to evoke emotion. Why else would you find yourself laughing at the hijinks of two actors who, offscreen, can’t stand each other? Or crying over the death of an actor who, when the camera is turned off, will dust himself off and grab a burger for dinner?

When I watch movies, it’s a little different. Each scene becomes a catalog card of possible social scenarios in my mind. If you ever find yourself arguing with a woman, try kissing her to throw her off guard. If you are in the middle of a battle and your buddy is shot, friendship means you have to go back under fire to rescue him. If you want to be the life of the party, say, “Toga!”

Later, if I find myself in that particular situation, I can shuffle through my file cards of movie interactions and mimic the behavior and know, for once, that I will be getting it right.

Incidentally, I have never cried at a movie.

Once, I was telling Jess everything I knew about dogs.

1. They evolved from a small mammal called miacis, a tree dweller that lived 40 million years ago.

2. They were first domesticated by Paleolithic cavemen.

3. No matter the breed, a dog has 321 bones and 42 permanent teeth.

4. Dalmatians are born all white.

5. The reason they turn in a circle before lying down is because when they were wild animals, this helped mat the long grass into a bed.

6. Approximately one million dogs have been named the primary beneficiaries in their owners’ wills.