The Medusa Plot — “39 Clues: Cahills vs. Vespers” Series

In the final book of “The 39 Clues” series, Amy and Dan bring the family together through forgiveness, and they work together to complete the hunt for clues. The kids return to normal lives but are warned that there is a family more evil than the Cahills, who is also hunting for the serum. They are the Vespers.

The Medusa Plot begins two years after the Cahills worked together when there is a worldwide abduction of seven members of the Cahill family. The same day, three Vesper agents attempt to kidnap Amy and Dan, but the kids’ counterattack keeps them safe. The family’s lawyer, William James McIntyre, tells the kids of the other abductions, and they receive a text from Vesper One on an untraceable cell phone delivered by helicopter. The message tells the kids to be in Florence, Italy, tomorrow or one of the hostages will die.

McIntyre, Sinead and Ian stay at the Cahill command center in Grace’s home to learn more about the Vespers and possibly learn the whereabouts of the hostages. Dan and Amy travel to Florence where they receive a message telling them to steal Caravaggio’s “Medusa” from the Uffizi Gallery, an almost impossible task. While Amy forms a plan to get the painting, Dan begins collecting the ingredients to make the serum that the Vespers want. He plans to drink it and put an end to the Vespers for good.

Hamilton and Jonah arrive with three fake “Medusas” and join Dan and Amy in the rescue. They accomplish the impossible, but when the “Medusa” is delivered to Vesper One, it is determined to be a fake as well. A video is sent to them of Nellie being shot in the shoulder.

Amy, Dan, Jonah and Hamilton begin a search for the original “Medusa.” They find that in 1966 the gallery was flooded, and a team of “Mud Angels” came in and rescued the artwork. The pieces were stored in an old church until the gallery was repaired. Jonah’s family had a file on the Mud Angels and discovered that one, Gregor Tobin, was a criminal wanted for theft. Amy and Dan set up a meeting with Tobin, tempting him with an ancient Egyptian sculpture Amy had kept from an earlier clue hunt. At Tobin’s home, Dan and Amy discover a hidden gallery behind a painting. Covering their faces, they throw a smoke bomb that knocks out Tobin and his security team.

In the secret gallery they find the “Medusa,” put it in their backpack and jump out the window. They climb down a cliff to reach Jonah and Hamilton, who are waiting in a boat. Tobin wakes and pursues them in a high-speed chase. Dan crashes the boat on a beach, and all passengers are thrown but still alive. Tobin believes them to be dead and the “Medusa” destroyed.

Amy protects the painting but the charger for the Vesper One device is lost in the crash, and the phone has a low battery. Ian and Sinead offer to build a new charger. When Ian goes for supplies, he recognizes the young man at the counter as Evan, Amy’s boyfriend. Evan identifies the phone in Ian’s picture and tells him that the phone is available only to the CIA and government agencies. Ian tells Evan about the Cahills and invites him to help them trace the phone. Evan is willing to do anything to protect Amy, but she is angry because she wants her personal life kept out of the adventure.

Dan finds a message in Italian or Latin etched into the frame of the “Medusa” and contacts his friend Atticus for a translation. The translation leads them to the “Gate of Life” at the Roman Colosseum. Vesper One has given them 96 hours for the next delivery, so the kids head to Rome before the handoff. Atticus phones Dan to tell him that he and his brother are at the Colosseum, and Dan answers the call a few feet behind them in line. Amy and Dan stay with Atticus because he is an expert on the Colosseum and believe he can help them find what they are looking for more quickly.

At the Gate of Life, they find a map on the wall of the tunnels under the Colosseum. The map is a replica of the “Medusa.” The snakes that are the Medusa’s hair intersect millions of times but only once bite each other. At this location, Amy and Dan find Leonardo DaVinci’s original “Medusa” shield and the original manuscript of The Travels of Marco Polo with an included epilogue.

Dan and Amy steal the manuscript and run, while Atticus is angry that his friend would steal a national treasure. They escape the tunnels and return to their hotel on the city bus. Atticus calls to warn them that his brother has reported them to the police. They are now on Interpol’s Most Wanted list. Dan and Amy hire a taxi to drive them from Rome to Florence.

Meanwhile, Sinead, Evan, Hamilton and Jonah travel to the factory that makes the Vesper One phone, hoping that it is also where the hostages are being held. They enter the factory with ease and find no hostages. They grab two phone chargers. On the way out, Hamilton triggers a bug in a vending machine that causes the whole factory to explode just after the four make it out. Ian saw a paper on the ground in the factory that had the symbol of his family line.

In Florence, Dan and Amy rent a room at a rundown hotel and change their appearances and names to avoid arrest. The handoff is to take place at a circus. During the final act, a trapeze artist swings down and takes the “Medusa” from them. A power outage sends the circus tent into chaos, and Dan and Amy are able to escape through a back exit. They find the trapeze artist lying on the ground with a syringe next to her. As she dies, her final words describe a character with burned or seared skin. Amy and Dan get a text saying the package has been received with an attached picture of all seven hostages still alive. Vesper One refuses to release the hostages until Dan and Amy complete a few more tasks for him. Dan is furious and wants to kill Vesper One. He continues his plans to remake the serum.

The final chapter identifies Vesper One posing as a taxi driver; no passengers are in his car, just the package.