Author David Baldacci, who is hosting a virtual field trip to the National History Museum, looks at artifacts that belonged to President Abraham Lincoln. (Sarah L. Voisin/The Washington Post)

When Amy and Dan Cahill turn up in Madagascar or Moscow, their fans don’t bat an eye. The young heroes of the “39 Clues” books are known for continent hopping to stop the evil Vesper clan’s plan to destroy the world. But the final installment in the “Cahills vs. Vespers” series has them visiting familiar territory for Kids­Post readers: Washington.

Day of Doom,” which was just published, takes the brother-and-sister team to the Smithsonian National Museum of American History for a clue that might help them keep the Vespers from using their Doomsday device on the world.

It’s no surprise that David Baldacci, the most recent of nine authors to write a “39 Clues” book, had some action take place in Washington. Baldacci lives in Northern Virginia and often includes the nation’s capital in his best-selling books for adults. Baldacci said he thought the Smithsonian was a natural tie-in for Amy and Dan’s most recent adventure.

“They’re always going around seeking information and knowledge,” Baldacci said. “What better place than to come here and use an American historical artifact . . . to get them where they need to go today.”

Baldacci also encourages kids to visit the Smithsonian by hosting a virtual field trip at the American History Museum called “Decoding History,” which can be seen at
beginning Tuesday at 1 p.m. In the 23-minute field trip, Baldacci and several of the museum’s American history experts share stories of some of the museum’s treasures, including one about a secret message in Abraham Lincoln’s pocket watch and the mysterious upside-down letter “V” in the Star-Spangled Banner.

The latest book in “The 39 Clues” series is "Cahills vs. Vespers: Day of Doom," by David Baldacci.

“I’m hoping that kids will find out that the things they have here are so extraordinary that you can’t help but be impressed,” he said.

Naomi McDonald, a 9-year-old fan of “39 Clues” from Takoma Park, doesn’t need much convincing. She loves both the American History Museum and “39 Clues.” Naomi said she’s happy the story is coming so close to home.

“They’ve basically never been sent to D.C., so it’s pretty cool,” said Naomi, who has read or listened to the first 16 “39 Clues” books.

She and brother Jonah, 7, said they were looking forward to “Day of Doom.” Clearly no fan of the Vespers, Naomi said she hoped Amy and Dan would put the evil family’s leader in his place.

“Basically I would like to see them finally meet Vesper One and finally demolish him.”

— Christina Barron