I groaned at the picture. Why, oh why, had Mom sent my little sister to technology day camp? Seriously. Second graders should not be allowed to text. It’s just annoying. I tapped out a reply to tell her to stop.

Believe it or not, she did.

My phone went quiet.

Too bad it was the only thing that got quiet. “FD?” shouted the woman in my closet. She pounded on the door. “This is outrageous. I insist you let me out this instant!”

Just so you know, I am not FD. And I was pretty sure I’d never met FD. In fact, I was pretty sure I’d never met the woman in my closet, either, except in the pages of some boring social studies book, or in a musty history museum, or maybe during one of my teacher Mr. Druff’s long, snore-fest lectures about “the incredible story that is America’s past.” He actually said that. He made us write it down in our social studies notebooks too.

“FD, are you still pouting about your speech to Congress?” the woman called out. “Truly, darling, no one noticed your zipper was down.”

I knew I had to open the door. I also knew that the second I did, things were going to get way out of control. I am not exaggerating. I’d experienced this blast from the past once before, and I needed just a few more minutes to brace myself. I mean, it wasn’t like I’d been expecting any . . . um . . . visitors today.

An hour earlier, my day had been pretty normal. I’d been lying on the family-room sofa reading another graphic novel--this one about an alien kid who crashed on Earth--while my irritating little sister, Olive, danced around the house in her brand-new mermaid Princess Aquamarina bathing suit. She was singing at the top of her lungs too. “Party, party, par-TAY! party, party, par-TAY!”

At first, I’d tried to ignore her by burying my nose deeper in my book. I do both these things a lot--ignore my sister and read graphic novels.

I love graphic novels.

I do not love Olive when she’s being annoying.

And boy, was she annoying. I knew she was really excited about the swimming party Mom was throwing for her eighth birthday that day. But geez, did she have to be such a pest?

“Knock it off,” I’d growled.

Olive scrunched her face at me. “Party party poop-ER! Party party poop-ER!”

I slammed my book shut and stomped up to my room.

Of course, she followed. “Come on, Nolan. We’re going to be late to my party.”

“I’m ready, already,” I grumbled.

Just as I was putting on my shoes . . .

POP! A bright light shot out from under my closet door. It grew white . . . whiter . . . crystal white. From deep within came the sounds of static and faint voices. A second later, my bedroom filled with the sound of a gazillion bubbles popping all at once. Then . . .

Bam! Bam! Bam!

Someone started banging on the inside of my closet door.

“It’s Ben!” Olive had cried. “He’s come back for my birthday!”

She flung open the door.

Screamed.

And slammed it shut again.

“That,” she panted, “is definitely not Ben Franklin.”

“Hullooo!” came a woman’s quavering voice. “FD? Is that you? Let me out, won’t you? I seem to have gotten trapped.”

At that moment, Mom hollered from downstairs. “Nolan! Olive! Is somebody up there with you?”

I swear our mother has the sharpest hearing in the universe. Maybe that’s why she’s the author-illustrator of the Bumble Bunny series of children’s books. Big ears come naturally to her.

Mom didn’t wait for us to reply. “It’s getting late!” she shouted. “Time to go to the party!”

Olive yelped and looked from the bedroom door to the closet door. “Now what?”

“You go,” I said urgently. “I’ll stay with . . . with . . . whoever.”

“But I’m dying to know who’s in there,” she whined. “I didn’t recognize her.” She reached for the knob. “Let’s take another peek.”

I leaped in front of her and pressed my back against the closet door. “And turn her loose in the house with Mom here? Are you crazy?”

“But--”

“You promised,” I whispered through gritted teeth. “You promised to keep all this--the crystal radio, Ben Franklin time traveling here from history--a secret until we figured it out, remember?”

She made a pouty face.

“I know you’re there, FD. I can hear you breathing,” the woman in the closet called.

“Remember, Olive?”

She nodded slowly.

“Then go!” I said. “Try to act normal. And whatever you do, don’t say a word about, er, this.”

“Olive!” Mom called from the staircase.

“Coming, Mother dearest!” she shouted back in this ridiculous British accent she’d learned from watching PBS. She crossed the room and stepped out into the hallway. “Pish posh, but it’s a lovely day for a party.”

Believe it or not, that was normal for Olive.

“Nolan, are you coming?” Mom called up.

I came out of my bedroom and stood on the upstairs landing, peering down at her. “I . . . I can’t.”

“But it’s your sister’s birthday.”

“It’s mermaid swimming, Mom. With a bunch of giggling eight-year-old girls.” I slapped on my most pathetic puppy-dog expression. “Please, can’t you give a guy a break?”

“Do let him stay, Mummy,” chimed in still-British Olive. “The big oaf will do nothing but ruin the party.”

Mom looked at me with laser eyes for a second. Then she nodded. “But stay in the house. And no friends.”

“No friends,” I promised. I figured it wasn’t a lie. How could the person in my closet be a friend if I’d never met her?

Mom looked at me another moment. Then they were gone.

And I was alone with the lady in the closet.

She knocked again. “Enough, FD. You’ve had your silly joke. Now open this door at once. Franklin? Did you hear me? I’m beginning to grow faint.”

So am I, I thought.

My belly felt tight and fluttery, like it was filling with bats. Beating their wings. Crowding my chest. Squeezing the air from my lungs.

Hand shaking, I reached for the doorknob . . .