Finn called a hello. No one answered. He took out his gun and started forward.

The lights were on in the front hall and what looked like the kitchen beyond. Finn stepped into the kitchen and saw Archer standing over a body.

Finn's gaze flicked from the body to the figure above it. The ghost glanced up. Their eyes met.

"Shit," Finn whispered, and looked away.

Gun poised, Finn began searching the house for Archer's killer. He made it through the front rooms and was heading to the bedrooms, when a voice behind him said, "You want some help with that?"

Finn hesitated then, not glancing back, continued on.

"I know you can see me," Archer said, stepping in front. "You looked right at me in the kitchen. You can hear me, too, or you wouldn't have paused when I spoke."

Finn lifted a finger, telling Archer to wait until he'd finished his sweep. Insensitive but necessary. He'd once been so engrossed in questioning a victim's ghost – and keeping the rest of the team from overhearing – that he'd missed the killer hiding behind the sofa. The only thing that saved him from a bullet was the guy's shock when he leapt out to discover the detective was talking to thin air.

So Finn continued his search, with Archer tagging along, calm and focused, as if he was just another officer on the scene. Finn met two kinds of ghosts: those too distraught to give a coherent account and those whose accounts were eerily coherent. They knew they were dead; it just hadn't sunk in yet.

They'd finished searching the spare room when Archer, heading out the door, went to pull it farther open for Finn, and his fingers passed right through. He stared at them, then did it again.

"Ah, shit." Archer's shoulders slumped.

"I'm sorry," Finn said.

Archer nodded. He kept staring at his hand, and Finn resisted the urge to pepper him with questions, knowing the clock was ticking and at any moment Archer could vanish.