Chapter One
Prologue

"Bright is the moon, high in starlight
Chill in the air cold as steel tonight
We shift, call of the wild,
Fear in your eyes
It's later than you realized"
Metallica: "Of Wolf and Man"

Kate Beckett knocked hesitantly on Richard Castle's door. He had disappeared from the precinct like a scalded cat the night before with a less-than-hopeful "good night" instead of his usual "until tomorrow" that had set her on edge.

Though the idea of a full day at her desk without him staring creepily while she filled out her post-arrest paperwork had sounded ideal at first, his odd, behavior the day before and sudden, unexplained departure had eaten at her the entire shift. She knew things were still fragile between them since she'd returned from her three-month, self-imposed exile after her shooting, but his behavior the past few days had been strangely erratic, even before he'd made his departure.

Though she knew rationally, there was no scientific basis for "full moon fever" she couldn't shake the old superstition out of hand. The day he'd been gone had, in fact, coincided with a full moon.

As put off as she was by his creepily staring at her whilst she filled out her DD fives after an arrest, her continuing therapy had her analyzing her feelings more than she used to. She may have her own problems, but it was becoming clear that something was up with her partner. Something she hadn't picked up on when she first came back. Maybe she didn't always show it as much as even she believed she should, but she cared about him, she just wasn't ready to face just how deep that went yet.

The door swung open just as Kate was about to retreat and she was rather taken aback to be standing face to face with Alexis instead of her father. Though the high school senior tried gamely to summon the disdain she had been carrying around since her father's return to the precinct, it was clear that something other than Kate Beckett at their door was bothering the young woman. Her skin was even paler than usual, her eyes were bloodshot and from the bags under them it was clear she hadn't slept well - if at all - recently.

Kate opened her mouth to ask after Castle but was cut off by a muffled howling like that of a wounded animal followed by thumping and banging from inside the loft. Her right hand instinctively parted her red trench coat and came to rest on her police issue Glock. She was about to push her way inside, but Alexis stopped her with a hand to her shoulder.

"Dad isn't feeling well," she offered dully, "we're watching horror movies in the office with the home theater on. Dad really likes the Underworld series."

"Of course he does," Kate thought to herself, unable to help the sharp pang of jealousy. "Kate Beckinsale in skin-tight leather, what's not to love?"

No sooner had the thought occurred to her, Kate remembered she was being watched by his teenage daughter and was suddenly mortified.

"Uhm…" she stammered. "Let him know I stopped by and that I hope he feels better soon."

"Uh… yeah," Alexis replied, apparently still distracted by the noises emmanating from the loft. "I need to get back, I was getting snacks from the kitchen."

Under normal circumstances, Kate would have been able to pick up on Alexis' clearly unconvincing body language, but between her own therapy session earlier that afternoon and her more recent mortification, she missed it. By the time she collected herself, the door had swung closed, cutting her off from further comment.

Alexis leaned heavily on the closed door, until the nightmare-fuel howling from behind the heavily reinforced security door of the safe room began again in earnest, followed swiftly by another round of pounding and the shrieking of claws on metal.

Not for the first time in the last two years, Alexis Castle prayed to whatever deity she could think of that her father wouldn't injure himself too badly before the sun came up and the beast finally released him.

It was always worse on the full moon.

*Author's note* I had toyed with the idea of going much darker with this, but in the end decided not to. I still have Cerberus Spectre to finish and I want to see how much of the third installment "The Spectre of War" I can get written before the winter ficathon starts.