I knew I had to tell Donnie what was happening, but I also knew if I did, he’d stop me from going back to Erin’s reality altogether. I figured I could take my own notes, keep track of things for another couple weeks, figure out how to come clean with everyone, and maybe discover a happy solution for us all, but it was becoming harder to keep track of my timelines. In one reality I lay in bed with Erin, looking out our small window at the snowy street, remembering how we’d promised go kayaking, only to realize that wasn’t in this reality at all. Next I was lying with Erin at the lake house, her room awash with the yellow glow of candlelight, and she was telling me about how she’d been getting interested in education reform, directly quoting passages from the dissertation my other Erin was working on. And then, late one afternoon, we were standing on her snow-dusted deck together, watching the light wane across the lake, and she was remembering the movie we’d seen on the night we’d met at the Film Club, a memory that was totally not hers.

A couple of geese were honking on the far side of the water, the first returns from their winter pilgrimage, and they floated along the defrosted edge, the sky darkening with evening. Somewhere, in another timeline, geese were probably returning to this same lake. Were they the same geese? Did they think the same goose thoughts? Was the lake house my future? That’s when we heard the other Erin banging on the front door.

“Open this fucking door!”

“Who is that?” Erin said, turning from the lake and sliding open the glass.

“Luke! Erin! I know you’re in there.”

“Oh my god, that sounds like me,” Erin said.

Then I was back in the lab looking at Donnie. “What the fuck, man?”

“Sorry,” Donnie said. “She came by to surprise you and saw the sexting notes on my desk. I had to tell her the truth. She pretty much forced me to send her there.”

“What? Put me back!”

“Listen,” Donnie said. “This whole thing was not okay. Like not for science, or you, or Erin, or me—”

“Just send me back for a couple minutes so I can explain things.”

“What’s wrong with you? You cheated on two versions of your girlfriend. Neither of them is going to want to talk to you right now. You need to give them space. Go home, smoke dope, get some sleep, come back tomorrow.”