Author:C. Alexander London
Publication Date:27 September 2016
Setting:Various Places
Preceded By:Mission Atomic, (Doublecross Book Four)
Followed By:N/A

Outbreak is a standalone book in the 39 Clues series, Superspecial. Written by C. Alexander London, it was released on 27 September 2016.


CALLING ALL CAHILLS! Announcing a 39 Clues Superspecial adventure -- the gang is back, and called to investigate one of their own: Sinead Starling


The Cahills are the most powerful family has ever known. For the past five centuries, they have secretly served as guardians of the world. The Cahill command presidents, take down corrupt governments . . . and are currently led by a fourteen-year-old boy with a superhero complex.

Dan Cahill may be young, but he's nobody's fool. So he knows he must act fast when he learns that Sinead Starling, a former friend who betrayed the family, is up to her eyeballs in a plot to control a deadly virus. But is Sinead behind the plot, or is she a hero trying to stop the virus from getting out? The search for Sinead will take Dan and his friends from Cuba to the Bermuda Triangle, where the fate of the world may just depend on whether the Cahills can trust a traitor.

Sneak Peek

Boston, MA

Dan ​Cahill knew a thing or two about collectors. When he was younger, he had collected baseball cards, autographs of famous outlaws, Civil War weapons, rare coins, and charcoal rubbings of tombstones.

For a while he had even collected casts, but he had broken bones that the size and smell of that particular collection had become, to quote his big sister, Amy, "disturbing." However the collector he was tracking through the streets of Boston was a different sort of collector entirely. Dan collected stuff he could geek on - meteor fragments, memorabilia from obscure sports, creepy photos he found at flea markets. The guy he had his eye on collected stuff he could sell for millions of dollars, stuff that was stolen from archaeology sites around the world and smuggled away from the countries to which they belonged: Buddhist relics from Cambodia, statues from Iran, religious carvings from Egpyt. The artifacts were priceless, sacred, and irreplaceable. They should've been in museums or left in the temples or tombs where they'd been found. They were the sort of things that someone might kill for. . . . .


Amy, Dan, Ian, Jonah, Cara and Hamilton are chasing a collector who happens to have stolen a historical sliver star. They engage with a private detective who so happens to want to sell the sliver star. When they go back into the mansion in Attleboro, they are visited by two CIA agents, Agent Pratt and Agent Gimler. The agents show the Cahills an image of Sinead stealing a genetically modified version of goat pox, one that affects humans. The cahills then accept the job the CIA agents have for them, to capture Sinead and stop an outbreak, hence the title Outbreak. One team, Cara, Ian, Hamilton and Jonah go to Sinead's previous house. The other, to Havana, Cuba.

Team one is in Sinead's old base or lab when a buch of people bust in with hazmat suits and weapons. Things take a turn for the worst when they accidentally get infected with the modified goat pox.


  • This will be C Alexander London's 2nd book, making him the first author not in The Clue Hunt to write multiple books.
  • While previous 1st books in series had gaps of more than six months after the end of the previous series, this book will come out only 3 months after its predecessor, Mission Atomic.
  • It is the fifth book in the series to have a single word title.
  • It is a standalone novel that may be the last 39 Clues book.
  • It is also the only book in the entire series to be for $13.99. All other main books have been for $12.99 in the US.
  • It has also been confirmed by Admin Sheila, that Outbreak will not have a Mission corresponding to it.


  • Book Cover Puzzle - ​(inverted) - ​Havana
  • Test Tube Page Puzzle - ​(inverted) - ​The cat can destroy the world
  • 39+ Pages Puzzle - ​(inverted) - ​Saladin rules
  • ​End Page Puzzle


Currently unknown if this will have cards. But since it doesn't have any mission nor the "Collect the Cards" in the cover, it might not have one.