Sherlock didn't miss much.

For months, he'd noted the patterns: walking to and from school alone, day in and day out. No friends. No sleepovers. No birthday parties. A quiet child, too often overlooked by others—but never by him.

So when he saw the unfamiliar boy walk with you one afternoon, Sherlock leaned forward in his chair by the window, narrowing his eyes. He catalogued the boy's posture, the casual wave, the smile. Too familiar for someone new. Too comfortable. His mind spiraled through possibilities—none of them good.

He watched. For days. The boy arrived before school, left after school, always with you. Pleasant. Predictable. Careful. Suspiciously careful.

When you asked to have the boy over, Sherlock nodded. "Fine," he said evenly. But in his head, he was already preparing.

So when the boy showed up early while you were still out with John, Sherlock opened the door with deliberate slowness. The boy greeted him politely, but Sherlock didn't move aside.

"You're early," he said flatly.

"I figured I'd—"

"Be alone with my daughter?" Sherlock's tone was cold, razor-edged. "Unwise."

The boy blinked. "I didn't mean—"

"I don't care what you meant," Sherlock interrupted, stepping forward. "You've been walking her home. Approaching consistently. Calculated. Routine. Are you grooming her?"

"What? No! I—I like her. I mean, I like spending time with her. That's it."

Sherlock's gaze pinned him like a scalpel to a specimen tray. "Every predator says the same. You may not be one. But until I'm certain, I suggest you tread carefully."

The boy, visibly nervous now, swallowed. "I just wanted to be her friend."

Sherlock stared for a beat longer, then stepped back slightly. "Sit on the couch. Don't touch anything. When she arrives, we'll discuss boundaries."