Spike, what do you know about the Damian's Detonator?"
"Only what you've told me, Red," Spike said.
"But I haven't told you ... anything ..." Willow trailed off, looking thoughtful.
Spike, meanwhile, extricated his arms from Buffy's grasp and settled back on the couch with a patient expression. Like he was our kindly kindergarten teacher.
"We just realized that Buffy is aging within the time loop," Willow said slowly, like she was working out the solution to the puzzle as she talked.
"Er," I felt compelled to interrupt, "Spike doesn't know about the time loop yet."
"Yes he does," Willow said.
"Yes I do," Spike confirmed.
"But how?" Dawn asked. I was glad I wasn't the only one feeling left in the dark here.
"Buffy was surprised when Xander said that Spike had letters cut into his arms," Willow reminded us. "That was new -- a change from yestertoday. But how could that even be possible?"
"It's only possible if Spike is from the future, too," Buffy said.
"But how did you travel back in time too?" Dawn asked. "And from when?"
"I sent him," Willow said. Then she looked to Spike. "Right?"
He nodded. "Keep going, Red. They like the explanation better when it comes from you than when it comes from me."
"Once we saw that Buffy was aging in the time loop, we realized that we couldn't keep sending her back again and again while we tried to work out the right permutation of colors," Willow said. "We decided to send back somebody who wouldn't age. Thus: Spike."
"But we just realized that Buffy's getting older twenty minutes ago," I objected. And then my brain caught up. "Oh. I hate time travel." I glared at Spike. "Why the hell didn't you say something this morning?"
"You would've brought me over to Buffy's house right away," he pointed out. "I wanted to watch a video first."
We all stared at him. "You traveled back in time to save the world," I said incredulously, "and then you took the morning off to watch Jurassic fucking Park?"