Today, I enter the sensory break room and make a beeline for the Koosh balls. Holding one in each hand, I wrestle my way into the swing and pull the material closed around me. “Morning, Jacob,” Ms. Agworth says. “You need anything?”

“Not right now,” I murmur.

I don’t know why people with AS are so sensitive to things like texture and color and sound and light. When I don’t look someone in the eye, and when other people very pointedly look away from me so they don’t appear to be staring, I sometimes wonder if I even really exist. The items in this room are the sensory equivalent of the game Battleship. Instead of calling out coordinates-B-4, D-7-I call for another physical sensation. Each time I feel the weight of a blanket on my arm, or the pop of Bubble Wrap under my body when I roll on it, it’s a direct hit. And at the end of my sensory break, instead of sinking my battleship, I’ve just found a way to locate myself in the grid of this world.

I close my eyes and slowly spin inside this dark, close ball. “Pay no attention to the man behind the curtain,” I murmur.

“What’s that, Jacob?” Ms. Agworth says.

“Nothing,” I shout. I wait until I’ve swung in three more slow pivots, and then I emerge.

“How are you doing today?” she asks.

It seems like a pretty gratuitous question, given the fact that I wouldn’t be in this room if I were able to tolerate sitting in class like neurotypical people. But when I don’t answer, she doesn’t pry. She just keeps reading her trivia books and jotting down notes.

The largest fish in the world is a whale shark, at fifty feet.

Four million marshmallow Peeps are made each day.

(That sort of makes me wonder who on earth is buying them when it’s not Easter.)

It takes the average adult man thirteen minutes to eat his dinner.

“I’ve got one for you, Ms. Agworth,” I say. “The word ass is in the Bible 170 times.”

“Thanks for that, Jacob, but it’s not really appropriate.” She shuffles her papers and looks down at her watch. “You think you’d be okay for a few minutes, if I ran down to the office to make some copies?”

Technically, she is not supposed to leave me alone. And I know there are certain other autistic kids who use the sensory room that she’d never stop watching like a hawk-Mathilda, for example, would probably fashion a noose out of the rope on the swing; Charlie would start tearing the shelves off the walls. But me, I’m a pretty safe bet. “No problem, Ms. A,” I say.

In fact, I am counting on it. And the moment the door closes behind her again, I pull the cell phone out of my pocket. As soon as I flip it open and press the power button, it lights up: little blue squares around each number, and a picture of Jess and Mark on the screen saver.

I cover Mark’s face with my thumb.

It’s Thursday, and today I’m allowed to call her. I already broke the rules and called her twice before from this phone-dialing her own cell number, even though I knew I would be automatically dumped into voice mail. Hey, so, this is Jess, and you know what to do.

I am already starting to forget the notes in the song of her voice.

Today, though, instead of hearing her message, I heard a tinny voice telling me that this wireless customer’s mailbox is full.

I’m prepared for this. I have memorized the phone number she gave me a week ago, the one that belongs to the new house. I dial it, even though I have to do it twice because it’s unfamiliar and the numbers get tangled in my head.

A machine picks up. Hey, this is Jess at the Robertsons’ house. They’re out of town, but you can leave a message for me!

I hang up and dial it again.

Hey, this is Jess at the Robertsons’ house.

I wait till the beep, and then I hang up. I turn off the power button on the cell phone, too. Then I speak my message, the same words I say to her every Thursday: See you in three days.

By Thursday, Jacob looks like the old Jacob, but he still isn’t back to normal. I can tell by the way he’s distracted-I’ll set a full dinner plate down in front of him and he won’t eat until I remind him that it’s time to pick up his fork and dig in-and by the moments I catch him rocking or bouncing on the balls of his feet. His meds don’t seem to be helping. And I’ve heard from teachers at his school that he’s been spending nearly half the day in the sensory break room.

I’ve called Jess Ogilvy twice, but her voice-mail box is full. I’m afraid to bring her name up to Jacob, but I don’t know what else to do. So after dinner on Thursday, I knock on the door of his bedroom and let myself inside. “Hi,” I say.

He looks up from a book he is reading. “Hey.”

It took me two years to realize that Jacob had not learned to read along with the rest of his kindergarten class. His teacher said he was among the most gifted language arts students, and sure enough, every night, he would pick out a book from a big basket in his room and read it aloud. But one day I realized that what everyone assumed was reading was actually just Jacob’s photographic memory. If he’d heard the book once, he could spit it back. Read this, I had said, handing him a Dr. Seuss book, and he’d opened it up and started the story. I’d stopped him, pointing to a letter.

What’s that?

A B.

And what sound does a B make?

He hesitated. Buzz, he said.

Now, I sink down beside him on the bed. “How are you feeling?”

“Interrupted,” Jacob says.

I take the book out of his hands. “Can we talk?” He nods. “Did you and Jess have a fight on Tuesday?”

“No.”

“When you went to her house, she didn’t say anything to upset you?”

He shakes his head. “No, she didn’t say anything.”

“Well, I’m a little lost here, Jacob, since you came home from your tutoring session very upset… and I think there’s still something bothering you.”

Here is the thing about Asperger’s syndrome: Jacob won’t lie. So when he says he didn’t have an argument with Jess, I believe him. But that doesn’t mean he wasn’t traumatized by something else that relates to her. Maybe he walked in on her having sex with her boyfriend. Maybe he got freaked out by her new residence.

Or maybe it has nothing to do with Jess, and he ran across an orange construction zone sign on the way home that required him to take a detour.

I sigh. “You know that I’m here when you’re ready to talk about it. And Jess, too. She’s there if you need her.”

“I’m going to see her again on Sunday.”

“Same bat-time,” I say. “Same bat-channel.”

I hand him back his book and realize that tucked beneath his arm is the old Jemima Puddle-Duck toy he used to carry as a child. Jacob carried her so fiercely that I had to sew a leopard cape onto her back because her fur kept rubbing bald. It was a ritual piece, according to Dr. Murano-something Jacob could hold to calm himself down. She described it as a way to reboot, to remind him that he’s all right. Over the years, Jemima was retired to make room for more discreet objects that could be tucked in his pockets: a photo-booth strip of the two of us, so folded and faded you could barely see our faces; a small green pebble a teacher brought him back from Montana; a piece of sea glass Theo gave him for Christmas one year. In fact, I haven’t seen this stuffed animal in ages; she’s been buried in his closet.

It is hard to see your eighteen-year-old son clutching a stuffed toy. But that’s what autism is, a slippery slope. One minute, you convince yourself that you are so far up that hill you can’t see the bottom anymore, and the next, it’s covered with black ice, and you are falling fast.