You find the answer on day seventy-eight.

Not in the books MC brought you — those gave you the framework, the theoretical language, the vocabulary of a science that this city has been building for decades. Not in the technical manuals from the Association library — those gave you the equations, the models, the closed-loop systems you laughed at because they're wrong.

You find the answer in Ever Group's files.

The hack takes eleven hours. Not because it's difficult — your brain provides the architecture, the same accelerated cognition that built scanners and scramblers and network taps from scrapheap components. It's difficult because Ever Group's security is layered in ways you haven't seen before. Not walls — mazes. False directories that loop back on themselves. Encryption keys that change every ninety seconds. Honey traps disguised as classified files, designed to catch exactly the kind of intrusion you're attempting.

Your nosebleed starts at hour four. By hour eight, you've burned through two meals and a litre of water and your hands are shaking with the particular tremor that means your body is spending resources faster than it can replace them. By hour eleven, you're through.

The file is buried deep. Not in the main research databases — those are impressive but public-facing, designed to be found by people with the right clearance. This file is in a partition that doesn't appear on any directory tree. A private archive, maintained by someone with system-level access, containing data that Ever Group's board of directors probably doesn't know exists.

The file is about the Aether Core.

Not MC's specifically — the Aether Core as a phenomenon. Its physics. Its energy signature. Its relationship to the dimensional structure that separates this world from everything else. The file contains seventeen years of research, compressed into technical language so dense that your brain has to shift into the accelerated mode just to parse it, and what it says is this:

The Aether Core is a dimensional anchor.

Not a power source — an anchor. A fixed point in the fabric between dimensions, stable enough to serve as a reference coordinate for interdimensional navigation. The energy it produces isn't just energy. It's a signal. A beacon that broadcasts across the dimensional barrier, marking this specific point in this specific reality with a frequency that nothing else in existence can replicate.

You sit at the desk in MC's living room and you read that paragraph three times.

A dimensional anchor. A fixed point. A beacon.

A door.

The calculations you've been building for weeks — the theoretical framework for a portal, the mathematics of punching a hole between here and home — they've all been missing a variable. The power source. You know how to build the key. You've known for weeks. But a key without a lock is just a piece of metal, and the lock is an energy source powerful enough to tear a hole in the dimensional barrier and hold it open long enough for a human body to pass through.

The Aether Core is that energy source.

MC's Aether Core.

The one in her chest. The one you stabilised on day one. The one that beats with the steadiness you gave it, humming its constant frequency, broadcasting its signal across dimensions like a lighthouse that doesn't know it's shining.

You close the file. You close the laptop. You sit in the dark of MC's living room — she's asleep, it's three in the morning, the apartment is quiet except for the refrigerator and the distant traffic and the sound of your own breathing — and you let the implication land.

You can go home.

The maths works. Your polymorph cells can interface with the Aether Core's energy — you've already done it once, on the bench, when your body reached into MC's chest and stabilised the frequency without knowing what it was doing. If you do it again — deliberately, with calculation instead of instinct, with the full architecture of your research behind it — you can use the Core's energy to open a portal. Your cells become the key. Her heart becomes the lock.

You can go home.

The cost is MC.

Not her life — probably. The file includes stability calculations, threshold estimates, the particular mathematics of how much energy can be drawn from an Aether Core before the host body begins to fail. The numbers suggest that a controlled extraction — careful, measured, with your polymorph cells regulating the process — would leave MC alive. Weakened. Destabilised. The heart you fixed would stutter again, the memories you unlocked would fragment, the woman who gave you a jacket and a desk and a name would be set back to where she was before the bench.

Probably.

The word sits in your mathematics like a crack in a foundation. Probably alive. Probably survivable. Probably not fatal.

You don't do probabilities with people's lives. You don't do probabilities with the life of the woman who found you in a basement and carried you up the stairs without asking for anything except the chance to feed you.

You open the steno. You write the calculations. All of them — the portal architecture, the energy requirements, the interface protocol, the extraction sequence. You write them in the spider-ink shorthand that nobody in this city can read, in handwriting so small that you need the desk lamp angled precisely to see the symbols.

You fill fourteen pages.

Then you write one more line, at the bottom of the last page, separate from the mathematics:

The cost is her.

You underline it. You close the notebook. You put it at the bottom of the stack — under the frequency charts, under the city maps, under the supply chain analysis and the Evol classification tables and everything else that doesn't matter anymore because you've found the thing that matters and it's the worst thing you've ever found.

---

Day eighty. Jenna comes to the apartment.

Not for you — for MC. A work visit, tactical briefing, something about a Wanderer incursion pattern in District 5 that needs Alpha Team's attention. Jenna arrives in uniform, takes off her boots at the door — a habit MC has apparently taught her — and sits at the kitchen counter with a tablet and a mug of coffee.

You're at the desk. Steno open. You don't look up when Jenna enters. You've learned to tolerate the uniform — not accept it, not trust it, but tolerate it the way you tolerate the sound of the refrigerator. A constant that isn't dangerous.

Jenna tolerates you too. She's been to the apartment four times now. She doesn't stare at you. She doesn't ask questions. She treats you the way she treats the furniture — present, unremarkable, part of the landscape.

Until today.

"Hey," Jenna says. Not to MC. To you.

You look up. Jenna is watching you from the kitchen counter, coffee in hand, tablet forgotten. Her expression is neutral — professional, the particular blankness of a military officer who has trained herself to be unreadable.

Then she says your name.

Not "hey you." Not "the girl." Your name. The one you gave MC on day sixty-two, the one that has existed in this apartment like a secret between two people, the one that MC apparently shared with her team leader because MC trusts Jenna with things like that.

Your pen stops. Your chest does the thing — the tightening, the particular response to being named in a world where nobody knows you. But this time it's different. This time the name doesn't come from MC's careful, deliberate kindness. It comes from Jenna's casual professionalism — the offhand way she says it, like it's just a name, like you're just a person, like there's nothing remarkable about addressing a fugitive polymorph by her first name over coffee at eight in the morning.

Two people in this city know your name now. Two people can find you by calling out in a crowd. Two anchors in a world you're planning to leave.

"Yes?" you say.

"MC says you read Association technical manuals for fun."

"I read them for information. The fun is incidental."

Jenna's mouth twitches. Not quite a smile. "There's a research symposium next month. Dimensional physics. I can get you the proceedings — published papers, not classified material, but the latest work on rift mechanics and Wanderer origin theory."

You stare at her. The offer is unexpected — not the generosity, but the specificity. Jenna isn't guessing at what you need. She knows. Which means MC talked about your research. Which means MC has been paying attention to the subjects you study, the books you request, the particular trajectory of your work.

MC knows you're building something. She doesn't know what.

"That would be useful," you say. "Thank you."

Jenna nods. Goes back to her tablet. MC comes out of the bedroom, and the briefing starts, and you sit at the desk with your steno open and your pen still and the fourteen pages of portal calculations buried at the bottom of the stack.

Two people know your name. One of them has a heart that could send you home. The other just offered you the research that might make it possible.

You write in the steno. Not calculations this time. A question:

If the cost is her, and she's the one helping you pay it — what does that make you?

You don't answer it. You don't know how.

Day eighty.