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About The Book

Shortlisted for the Edgar Award for Best Mystery

“Mystery lovers will be satisfied by the plot and adults will love the curriculum and social awareness tie-ins.” —School Library Journal

Eleven-year-old Luis is left looking for answers after a city-wide blackout leads him to an electrifying mystery in this edge-of-your-seat thriller from Martha Freeman.

Luis Cardenal is toasting a Pop-Tart when a power outage strikes Hampton, New Jersey. Elevators and gas pumps fail right away; soon cell phones die and grocery shelves empty. Cold and in the dark, people begin to get desperate.

Luis likes to know how things work, and the blackout gets him wondering: Where does the city’s electricity come from? What would cause it to shut down?

No one seems to have answers, and rumors are flying. Then a slip of the tongue gives Luis and his ex-best friend Maura a clue. Brushed off by the busy police, the two sixth graders determine they are on their own. To get to the bottom of the mystery, they know they need to brave the abandoned houses of Luis’s poor neighborhood and find the homeless teen legend known as Computer Genius. What they don’t know is that someone suspects they know too much, someone who wants to keep Hampton in the dark.

In this highly charged mystery, two can-do sleuths embark on a high-tech urban adventure to answer an age-old question: Who turned out the lights?


Luis hit the button again, hit it hard. Still, the bulb stayed unlit. This close to throwing the whole thing across the room, he stopped himself. If the noise woke his mom, she’d be mad. She was back on nights.

What Luis did instead was grab his phone and call the only other person he knew who had entered the science fair—Maura Brown.

“Did you follow the directions?” she asked.

“Yeah, I did. There’s gremlins in the wires or something.”

Luis Cardenal was eleven and in sixth grade. He was average height. His shoulders were beginning to broaden, but he still looked more skinny than strong. Luis had a mane of black hair and eyes that were almost as dark. His mom said he’d be a good-looking kid—guapísimo—if only he’d get a haircut and maybe smile once in a while.

When his mom said that, Luis pulled his lips back from those teeth and made what Maura called his fierce face. This was a joke between them but not entirely a joke. Luis wasn’t really angry the way he looked. More like he was determined, and the smile his mom wished for did not fit with determined.

Maura was Luis’s best friend. Ex–best friend. Ex-best but still friend. Her hair was red-blond and thick. She had pale skin with freckles, and her eyes were blue. Her nose was so small that Luis had asked her once how she even breathed out of it.

She had socked him in reply, and he’d never asked again.

Now she said, “There are no gremlins.”

“Maybe not in your science fair project,” Luis said.

“It’s a science fair project?” Maura said. “How lame is that—a lightbulb?”

“A lightbulb that won’t light,” Luis clarified. “So what’s yours that’s so great?”

“It’s a replica of the first kidney dialysis machine,” Maura said. “This Dutch doctor invented it right before the Nazi invasion. I mean, mine’s going to be smaller and you can’t hook it to a live body, or anything, but it turns out to be not that hard to build. You get plastic wrap and orange juice cans—”

Luis stopped listening. The Nazi part had sounded interesting, but he didn’t know what a di-whatzit machine was, and he sure as heck wasn’t going to ask. Maura had a lot to say about her project, so while not listening he fiddled with the faulty circuit that lay in front of him on the floor of his blue bedroom—dark blue for Blue Lu.

It had taken a lot of talking, but finally last spring Luis had convinced his parents to let him claim the big bedroom that used to belong to his older brother, Reynaldo. Then he had hung up some posters scrounged from here and there—LeBron James, Kyrie Irving, Steph Curry. On his desk was a chessboard set up for a game. Reynaldo had promised Luis he would teach him to play; Luis was still waiting. The carpet on which he sat now was brown and threadbare, flattened by the soles of countless shoes.

There was a one-hundred-dollar prize if you won the science fair. It was definitely worth a try. To get what he needed for the project, Luis had braved the basement. Most of it was junk down there, but if you were determined, you could find almost anything—in this case electrical wire from the cord of a busted lamp, a nine-volt battery, a switch, and a bulb from an old flashlight. Luis had followed directions looked up online to create a circuit—battery connected to wire connected to switch connected to bulb, then back to wire and battery.

Maybe the battery was dead? But it looked brand-new.

Now Maura was talking about kidneys. Luis had heard somewhere that you could test a battery with your tongue. It sounded weird, but—“Ow!”

“Luis! Are you okay?” Maura’s voice came from the floor.

“Thorry,” Luis said, his tongue not working right, then, “Thorry,” again when he had picked the phone up. “Don’t evuh wick a battewy, Mauwa. It huwts—and it tastes tewwibuh.”

“Why would I do anything that dumb?” Maura asked.

“No reason.” The terrible taste was still there, but his tongue was recovering.

“Do you want me to come over and take a look at your project? Is that why you called?” Maura asked.

“You sound like a mom on TV, Maura: ‘Don’t make me come down there!’?” said Luis.

There was a pause. Was she insulted?

Anyway, the fact was he did want Maura to come over. Who else was going to help him? Reynaldo would have, but he’d be at work at the garage. He worked all the time. Luis’s parents were working, too, and anyway what did they know about science fair projects? They had gone to school in a Nicaraguan village. According to them, the school had dirt floors and one beat-up science book the whole class had to share.

“Forget it,” he told Maura. “I’ll figure it out, or I won’t. You’re right. It’s a stupid project anyway.”

“I’ve got my bike,” Maura said. “I’ll be there soon.”

About The Author

Photo courtesy of the author

Martha Freeman worked as a reporter and teacher before becoming a full-time writer of books for young readers, including the Edgar Award–nominated Zap!Born Curious, The Secret Cookie Club series, Who Stole Halloween?, and Effie Starr Zook Has One More Question, which School Library Journal called “accessible and exciting” in a starred review. She also collaborated with NASA astronaut Mark Kelly on the Astrotwins books. Martha lives in Oregon. Learn more at

Product Details

  • Publisher: Simon & Schuster/Paula Wiseman Books (May 7, 2019)
  • Length: 304 pages
  • ISBN13: 9781534405585
  • Grades: 3 - 7
  • Ages: 8 - 12
  • Lexile ® 660L The Lexile reading levels have been certified by the Lexile developer, MetaMetrics®

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Awards and Honors

  • Bank Street Best Children's Book of the Year Selection Title

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More books from this author: Martha Freeman