Three weeks.
That was how long it took before the basement stopped feeling like two separate groups sharing a space and started feeling like one group that had always been that size.
It didn't happen all at once. It happened the way most real things happen, gradually and without announcement, in the accumulation of small moments that didn't seem significant individually but added up to something that mattered.
It happened the morning Samantha beat Kristen in a sparring match and Kristen said okay that was genuinely impressive with the specific tone she used when she meant something completely and Samantha almost smiled and then did smile, the full one, not the almost.
It happened the afternoon Jasper was sitting in the corner of the basement between drills communing quietly with whatever he communed with and Niall came and sat beside him without being invited and without asking questions and just kept him company in the comfortable silence of someone who understood that a person could need company and quiet at the same time.
It happened the evening Engel was in the kitchen making something that smelled like his grandmother's recipe and Thomas came in and stood at the counter and they talked for two hours about the old war and what they remembered of it and what they wished they could forget, two men who had been carrying the same history from different angles for a long time, and when Katherine passed the kitchen door she heard them laughing about something and felt the particular warmth of a sound she hadn't expected.
It happened the night Grace and Tierney sat on the back porch after everyone else was asleep and talked until very late about things Katherine didn't know and wasn't meant to know, two women who had taken different paths through the same difficult world and had arrived at the same place by different routes and were only now getting to compare notes.
By the end of the third week the basement sessions had developed their own rhythm.
Thomas ran the mornings. Weapons work, channeling, the technical precision of learning to use power in a controlled and deliberate way rather than a reactive one. He was exacting and patient in equal measure and he had the gift of knowing which one a particular person needed at a particular moment, which was rarer than it sounded.
Tierney ran the afternoons. Combat application, situational awareness, the unglamorous work of learning to think clearly when everything around you was trying to make thinking clearly impossible. She sparred with each of them personally and she did not go easy on anyone, which they had all learned by now was the highest form of respect she knew how to offer.
Dean worked with whoever needed extra time in the evenings, quietly and without making it feel remedial, just an extension of the day, one more hour of practice framed as optional that everyone always took.
And Engel had begun doing something that nobody had formally asked him to do and everybody had tacitly accepted as essential, which was working with Samantha and then with the others on something he called reading the field, the ability to feel the movement and intention of people and power around you before you could see or hear them, the kind of awareness that came from decades of paying attention to a world most people couldn't see.
Katherine had taken to it immediately because it was not entirely different from what she already did, that internal turning of her power that listened for signals. Jasper had taken to it with a quiet intensity that suggested it was simply a formalization of something he had been doing his whole life. Samantha had taken to it like breathing.
The others were getting there.
It was an afternoon in the third week when things shifted.
They were running a full group drill, all of them on the basement floor, the most complex they had attempted, two teams working against each other with Thomas calling adjustments from the side, and it was going well in the way that things go well when everyone in the room knows what they are doing and trusts the people beside them to do the same.
Samantha and Katherine were working together for the first time in a real drill context, and something happened between them that neither of them had planned for.
Katherine sent a wave of heat toward the opposing team and Samantha caught it, not blocking it, catching it, and wrapped wind around it the way wind feeds a fire, and what came out the other side was something neither of them had made individually, a rolling column of superheated air that moved faster and hit harder than anything Katherine had produced alone.
They both stopped.
Looked at each other.
"Did you mean to do that?" Katherine asked.
"No," Samantha said. "Did you?"
"No."
Thomas had stopped calling adjustments and was looking at the space where the column had dissipated with an expression that was calculating and intrigued.
"Do it again," he said. "On purpose this time."
They looked at each other again.
Katherine felt for her fire element and let it build slowly, deliberately, and extended it outward toward Samantha the way she had learned to extend the signal, lightly, without grasping.
Samantha felt it and did what wind does naturally around heat, fed it, shaped it, gave it direction and speed without changing what it essentially was.
The result was cleaner this time and more controlled and significantly more powerful than either of them could produce independently.
Carlyle made a low sound of appreciation.
"That's a combination ability," Engel said from the wall where he had been watching. "Two elements working in concert. It is rare and it is very difficult to control." He looked at his daughter. "You have been practicing the foundation of that your whole life without knowing it."
Samantha looked at her hands and then at Katherine.
Something passed between them in that look, the recognition of two people discovering that they are better together than apart, that the particular thing each of them carries fits with what the other carries in a way that makes both things larger.
It was Jasper who said what everyone else was thinking.
"Can the rest of us do that?" he asked.
"That depends on the elements," Thomas said. "Some combinations work naturally. Some require more development. Some—" He looked at Katherine meaningfully. "Some are more complex because of the number of elements involved."
"We should figure out all of them," Niall said, already looking around at the group with the particular expression he got when he was mentally mapping a problem from multiple angles at once. "Who works with who. What combinations produce what. Make it systematic."
"He's right," Carlyle said.
"Obviously I'm right," Niall said. "I'm frequently right. People underestimate how frequently I'm right."
"Nobody underestimates that, Niall," Kristen said.
"You slightly underestimate it."
"I really don't."
"We can start mapping combinations tomorrow," Thomas said, cutting through it with practiced ease. "Tonight—"
He stopped.
The basement went quiet.
Not because Thomas stopped talking, but because something changed in the quality of the air in the room, a shift that Katherine felt in her power before she understood it with anything else, a presence that was familiar and specific and that never arrived without meaning something.
KaSandra was in the basement.
She hadn't come down the stairs. She was simply there, in the far corner near the weapons rack, her golden eyes lit in the low light of the basement, her dark coat around her, absolutely still.
Everyone turned.
The room held its breath.
KaSandra looked around at all of them, at the full assembly of the group that had been building toward this for months, and her expression was doing something complicated that Katherine had not seen on her face before, a layering of things that were not easy to separate, gravity and pride and the specific weight of someone who is about to deliver news they have been carrying alone for too long.
She looked at Tierney first.
Then she looked at the room.
"I need everyone to listen," she said. "What I am about to tell you is not something I was certain of until today and I would not be here if I were not certain."
Nobody moved.
Nobody spoke.
KaSandra let the silence confirm that she had the full attention of every person in the room.
"Victor has hired from the assassination clan," she said.
The words landed in the quiet like something dropped from a great height.
"He has sent an assassin," she continued, her voice staying level and even, the voice of someone delivering a diagnosis, precise and without ornament. "Not to find you. Not to capture you." She paused. "To hunt you. This assassin has been given one instruction. Dismantle this group by any means necessary."
The basement was absolutely silent.
Katherine looked at her mother.
Tierney's face was still, that particular controlled stillness that meant she was processing something dangerous and choosing not to let the danger of it show before she had finished processing it.
Dean had straightened from the wall and his eyes had gone to that specific focused quality they got when something shifted from potential threat to actual one.
Thomas had set down what he was holding.
"How long do we have?" Thomas asked.
"I don't know," KaSandra said. "The assassination clan does not operate on predictable timelines. That is part of what makes them dangerous." She looked at Thomas steadily. "What I know is that the assassin has already been dispatched. They are already moving."
"Toward here?" Dean asked.
"Toward all of you," KaSandra said. "Wherever you are."
Jasper was very still beside Courtney. Samantha had moved slightly closer to Engel without seeming to realize she had done it. Engel was looking at KaSandra with the expression of a man who had heard bad news before and knew the first thing to do with it was simply to receive it clearly.
Katherine looked around the basement at all of them, at this group that three weeks ago had been two separate things and was now one thing, at the faces she had learned to read and the powers she had watched develop and the people she had come to trust with a completeness that still sometimes surprised her with how absolute it was.
Then she looked at KaSandra.
"Tell us everything you know," she said.
KaSandra looked at her.
"That," she said quietly, "is exactly what I came to do."