A brittle chill settled over Kaer Morhen as autumn deepened, the fortress's wooden walkways frosted with the first ice. Visenna's laboratory glowed with lamplight against the dusk, its shelves heavy with jars of herbs and vials of experimental serum. On the central table lay rows of small crystal cages—Geralt's mouse cohorts for the latest Trial of the Grasses simulations. The survival rate hovered stubbornly at fifty percent, far improved from spring's dismal numbers but still short of the sixty percent threshold.
Geralt arrived just as Visenna was preparing the next batch of mutagenic elixir. His mother's eyes were rimmed red, her movements brisk but tense.
"Hello, son," she said without warmth. "We've identified a new catalyst to test—swamp bloom extract. Vicky discovered it during our last excursion."
Geralt set aside his satchel of harvested herbs and nodded. "I've processed the bloom into a concentrated tincture. It's ready."
Visenna examined the lab notes. "Good. We'll substitute ten percent of the drowner fiber infusion with this extract. It may stabilize the mutations."
They worked side by side, crushing pale blue petals into a fine paste, weighing precise portions of drowner tendon fiber and nekker scale dust. Moonlight streamed through the iron-barred window, lending the chamber an otherworldly glow.
As Geralt heated the infusion, Visenna supervised the temperature—first a gentle simmer, then a brief boil. He stirred continuously, the serum's color shifting from sickly green to a deep emerald. The swamp bloom's compounds reacted unpredictably, causing wisps of luminous vapor to coil around the cauldron's rim.
"It's volatile," Geralt warned. "We should ventilate."
Visenna waved a hand, casting a soft ward that absorbed harmful fumes. "Keep stirring. We do not venture through fire unprotected."
Their united concentration was a balm to Geralt's soul. Each moment in the lab with his mother—rigorous, precise, collaborative—strengthened the bond between them. Yet a shadow of dread lingered: the more potent the formula became, the greater the risk during full-scale human trials.
The Reckless Experiment
Late that night, after the serum cooled and was decanted into test vials, Geralt insisted on a preliminary experiment beyond mice. "We should verify stability over 24 hours," he suggested. "Just one small dose."
Visenna hesitated. "The protocols require extended observation and careful dosage. You know the risks."
"I know," Geralt replied, voice firm. "But I'm ready."
Visenna closed her eyes, torn between scientific caution and maternal fear. "Be careful," she whispered, placing a protective ward over him. "If anything goes wrong, call out immediately."
Under the ward's soft glow, Geralt drank the serum. A chill rippled through his veins, followed by a surge of warmth—then the first pangs of the mutagenic process. His muscles ached, his vision shimmered, and he staggered against the table.
Visenna rushed forward, invoking a healing spell as Geralt collapsed. Her magic surged around him, but the serum's combined mutagens overwhelmed her wards in moments. The chamber filled with toxic steam as the potion's exotic compounds began reshaping his physiology with unprecedented speed.
"Geralt!" she cried, pounding on his chest. "Stay with me!"
Through a haze of pain, he heard her voice—urgent, terrified. Vesemir burst in through the laboratory's heavy door, his grizzled face pale in torchlight.
"Clear the fumes!" he barked. He broke some vials to create a makeshift arcane filter, chanting elder runes. The noxious vapor dissipated, but Geralt's breathing labored.
Visenna knelt beside her son, weaving a complex healing weave to counteract rampant cellular mutation. Vesemir applied quick-draw potions to stabilize his heart rate. Minutes stretched like eternity.
Finally, Geralt's chest rose in a shallow breath. Visenna wept as she soothed his fevered brow. "My son…" she sobbed. "No more risks."
Geralt's hand reached for hers, trembling. "I'm sorry. I thought—" His voice faltered.
"You thought you could master this alone," she whispered. "But I need you alive."
Vesemir's stern voice cut through the anguish. "No more midnight experiments. We proceed only by the book, with full safeguards."
The lesson was immortal. Geralt had risked everything in a moment of pride. His mother's tears and Vesemir's chiding solidified his resolve: never again would he gamble with secrets that bound them all.
Over the next fortnight, Visenna and Geralt resumed the mouse trials with a renewed sense of caution. Each test followed exact schedules—staged doses over days, constant monitoring, and multiple control groups. The laboratory team expanded to include Jacob and Vicky, whose fresh eyes caught subtle deviations in behavior.
Late one evening, as the sixtieth mouse in the latest cohort emerged from its mutagenic transformation without adverse reactions, Visenna's excitement was palpable. "Sixty percent!" she exclaimed, tears of triumph mingling with fatigue. "We've done it."
Geralt allowed himself a rare smile. "Thanks to Vicky's bloom and rigorous protocols."
Vicky beamed. "Glad it wasn't my fault."
They celebrated quietly—warm tea, honey cake, and genuine relief. Visenna hugged her son tightly in a rare public display of affection among witcher folk. "I feared I'd lose you in my own workshop," she whispered. "But together, we saved these souls. And ourselves."
Geralt hugged her back, the pain still lingering in his muscles but overshadowed by love. "We did this together, Mother."
With the Trial of the Grasses formulas perfected, Vesemir approved human trials for the five friends whose loyalty had never wavered.