Dogpatch, 1 A.M.

You spend the evening learning that you don't have any friends.

You scroll your contacts on a bench in Lafayette Park while the fog comes in. Saanvi from the Berkeley lab: you haven't talked since her wedding, which you missed for a Kerrow launch. Anika from yoga: married to Kerrow's head of sales. The couple from the dinner party in Sausalito: Jarrett's friends, Jarrett's investors, Jarrett's people. Somewhere in six years every person in your life became a person in his.

Your mother would have known what to do. She would have put the kettle on and said, Well, Ava, my wren, what do you want?

Nobody has asked you that in a very long time.

At 10 p.m. you check into a hotel near Union Square with the credit card that still works. At 11 p.m. you read the separation agreement again. At midnight you read it a third time and notice that the non-compete starts "upon execution." Upon signing. If you never sign, it never starts.

At 12:40 a.m. you take the hardware store receipt out of your coat pocket and smooth it flat on the bedspread.

ILLINOIS ST, DOGPATCH.

You tell yourself you're just going to look.

Dogpatch at one in the morning is brick and fog and the smell of the bay. Old warehouses with new murals, a shuttered coffee place, the long silhouettes of the shipyard cranes standing over everything like patient animals. The cab drops you in front of a building that looks like it once made something heavy. A faded painted sign high on the brick still says MARINE CASTINGS.

A big roll-up door is stuck halfway open, tilted, like a mouth mid-yawn. Blue light and a deep, steady hum spill out under it.

He wasn't lying. The door is broken.

You duck under.

Inside, the warehouse is enormous and full of machines that sing. Rows of server racks stand under old iron crane rails, their fans roaring softly, their status lights blinking green and amber. Cables run overhead on hand-built trays. A dozen desks are shoved together in the middle like an island. There are beanbags. There's a cot. On the cot a lanky young man with white-blond hair sleeps with his glasses pushed up on his forehead and a laptop on his chest.

At the back, sparks fly. A huge man in a welding mask is fixing a rack frame. He flips up the mask when he sees you, revealing a broad, friendly face and a short beard.

"Hey. You must be Ava," he says, like women walk in at one in the morning all the time. "You looking for Raff?"

"I, um. Yes."

"RAFF," he bellows, gently, which you didn't know was possible. "SHE CAME."

The blond kid on the cot jerks awake. "Who came? Is it the fire marshal?"

"Go back to sleep, Kipp."

From a glass-walled office on a mezzanine, Rafferty Blaine comes down a set of metal stairs two at a time. He's in a gray work shirt now, sleeves pushed to the elbow, forearms freckled with old little burn scars. He stops at the bottom and looks at you. He doesn't look surprised.

"It's not three yet," he says.

"I couldn't sleep."

"Nobody here can. It's a whole culture." He nods at the big man. "Sione Tavita, hardware, operations, everything that would catch fire without him. That's Kipp Lasku, my CTO, who is pretending he's still asleep."

"I am asleep," Kipp says, eyes closed. "I'm having a nightmare that Kerrow's wife is in our building."

"Kipp."

"What? It's a valid nightmare."

"Her name's Arroyo," Rafferty says. Flat. Final.

You look at him. You never told him your maiden name. "How do you know that?"

"I read things." He turns. "Come on. I'll show you why I'm the ghost."

He takes you up to the mezzanine office and pulls three folders out of a filing cabinet. Real paper. Old-fashioned. He lays them out on the desk like a hand of cards.

Oregon. Long Beach. The hospital network.

Inside each one are printouts: side-by-side outputs, Gantry on the left, Lattice on the right, the same questions, and his handwriting in the margins. How does it know to stop here? Why does it back up? WHO WROTE THIS.

That last one is underlined so hard the pen went through the paper.

"Four years," he says. "I knew whoever built Lattice thought differently from anyone I'd ever hired. I just figured it was a team. A dozen people in a basement somewhere. Then you opened your mouth at the bar."

You touch the torn place in the paper. You don't know why it makes your throat close.

"Here's the offer," Rafferty says. "Plainly, because I'm bad at the other way. You get the lab. You get all the compute I have, which isn't as much as Kerrow and is more than enough for you. You get Kipp and Sione and the six others who'll show up at nine and be scared of you. And you get this."

He walks to the glass office door. It's frosted, with big black vinyl capitals across it at eye level: BLAINE.

He takes a box cutter from his back pocket, slides the blade under the edge of the B, and peels.

The letter comes off in one long curl. Then the L. Then the A.

"What are you doing?"

"Taking my name off the door." The I, the N, the E. He balls the vinyl letters up in his fist and drops them in the trash. The glass is blank now except for faint ghosts of glue. "Whatever you build here, it goes out under whatever name you want. Yours. A made-up one. I don't care. I want it to exist."

You stare at the empty glass.

"And the catch?" you manage.

"A deadline." He leans on the desk. "Twelve weeks from now is the Signal Summit at Pier 48. Your husband is launching Lattice 2 on the main stage. Opening keynote. Every buyer in the industry will be in that room." He meets your eyes. "I want you on the same stage, the same day, with something better."

Twelve weeks. To build an engine from nothing. Against your own work.

It's insane. It's the most exciting thing anyone has said to you in six years.

"One condition," you hear yourself say. "Clean room. I don't touch a single line of Lattice. Not from memory, not from muscle, nothing. If I build something, it has to be new, or they'll say I stole it."

"Good," Rafferty says instantly. "I'd have asked for the same."

"And I'm not signing his papers."

"Wasn't going to suggest it."

You look at the blank door for a long time.

"Okay," you say. "I'm in."

"Welcome aboard, Ava," he says quietly, and it sounds like a promise.

He gives you a laptop, a login and the lumpy couch in the office. "Sleep," he orders, and goes back downstairs to his own desk among the humming racks, where you can see the top of his dark head through the glass.

You don't sleep. You open an empty file.

For an hour you just think. Then, because your hands won't stay still, you write something small: eleven lines, a new way to let a model decide when it should stop and check its work. Not Lattice. Not even close to Lattice. Something that's been sitting in the back of your mind for a year with nowhere to go.

At 1:50 a.m. you push it to the repo. Then you close the laptop and lie back on the couch and stare at the ceiling and wonder what you've done.

Downstairs, a chair creaks. Then nothing for a long time.

At 2:04 a.m. your phone lights up on your chest.

An unknown number. You know exactly whose it is.

Merged your branch. I need to know how your brain works.