It makes it more multi-sensory.” I offer him the package of Oreos. He hesitates, unsure if it’s all right, hungry but unsure how many he can take without being rude. “Take as many as you want. I’ve already eaten ten, so you have some catching up to do.” He takes three. “Is there anything you’d like to see first?” He shakes his head. “Tell you what. Let’s go up to the third floor; that’s where they keep all the stuff that isn’t on display. Okay?”

　“Okay.”

　We walk through darkness, up the stairs. He isn’t moving very fast, so I climb slowly with him.

　“Where’s Mom?”

　“She’s at home, sleeping. This is a special tour, only for you, because it’s your birthday. Besides, grown-ups don’t do this sort of thing.”

　“Aren’t you a grown-up?”

　“I’m an extremely unusual grown-up. My job is to have adventures. So naturally when I heard that you wanted to come back to the Field Museum right away, I jumped at the chance to show you around.”

　“But how did I get here?” He stops at the top of the stairs and looks at me with total confusion.

　“Well, that’s a secret. If I tell you, you have to swear not to say anything to anyone.”

　“Why?”

　“Because they wouldn’t believe you. You can tell Mom, or Kimy if you want, but that’s it. Okay?”

　“Okay....”

　I kneel in front of him, my innocent self, look him in the eyes. “Cross your heart and hope to die?”

　“Uh-huh....”

　“Okay. Here’s how it is: you time traveled. You were in your bedroom, and all of a sudden, poof! you are here, and it’s a little earlier in the evening, so we have plenty of time to look at everything before you have to go home.” He is silent and quizzical. “Does that make sense?”

　“But...why?”

　“Well, I haven’t figured that out yet. I’ll let you know when I do. In the meantime, we should be moving along. Cookie?”

　He takes one and we walk slowly down the corridor. I decide to experiment. “Let’s try this one.” I slide the bookmark along a door marked 306 and open it.