It was a cool day. The sun was out, and the leaves were just changing. The other three, being English and used to colder weather, wore no coats. I did, and I pulled it tight around me as we walked down the busy streets, past some West End theaters and pubs, around a church and through Trafalgar Square. There were loads of tourists on the square, taking pictures of each other climbing on the huge lions at the base of Nelson’s Column, screaming as legions of pigeons swooped down at their heads. I didn’t really feel like a tourist anymore. I wasn’t sure what I was. I was definitely feeling increasingly self-conscious about being with these three, since I was a clear disruption to the routine and probably an annoyance, but feeling self-conscious was better than feeling crazy. They were ignoring me anyway and having a debate about paperwork.

“So then we fill out a G1 form . . . ,” Stephen was saying.

“What I don’t understand,” Callum replied, “is why we call it G1, since we only have one form. Can’t we just call it the form?”

“We only have one form now,” Stephen said, not looking up. “We might have other forms in the future. Also, G1 is actually shorter than the form.”

“Here’s a better question,” Callum replied. “Why have a form at all? Who’s going to check? Who’s going to care? No one knows we exist. No one wants to know we exist. We’re not taking people to court.”

“’Cause,” Boo said. “We need a record. We need to know what we did. We need it to train other people to do this job. And ghosts are still people. They were someone. Just because they’re not alive—”

“You know what? I think being alive should be a primary way of figuring out who is and who isn’t a person. I think that should be question number one. Are you alive? If yes, go on to question two. If no, you should not be reading this—”

“Oh, that’s such rubbish. One of my best friends happens to be a dead person.”

“All I’m saying is,” Callum said calmly, “since we can do this any way we want—and how often do you get that chance in life?—why did we choose to do this in a way that involves paperwork?”

“I can make a G2 if you want,” Stephen said magnanimously. “Just for you. Special form for interdepartmental incidents involving both the police and the transport system. We’ll call it Callum’s Form. A Callum 2A could be for the Underground. You’d get a Callum 2B for any incidents on buses. Maybe a Callum 2B-2 is any incident that takes place at a bus shelter.”

“I will kill you, you know.”