TimeRiders is a series of teen science fiction novels written by Alex Scarrow. The series has nine books and is published by Puffin Books.
 Liam O'Connor should have died at sea in 1912.
Maddy Carter should have died on a plane in 2010.
 Sal Vikram should have died in a fire in 2026.
 Yet moments before death, someone mysteriously appeared and said, 'Take my hand ...'
 But Liam, Maddy and Sal aren't rescued. They are recruited by an agency that no one knows exists, with only one purpose—to fix broken history. Because time travel is here, and there are those who would go back in time and change the past. That's why the TimeRiders exist: to protect us. To stop time travel from destroying the world...
 The TimeRiders series' summary
 The novels revolve around three teens who are recruited by an agency known as 'The Agency' just before their deaths. The Agency was set up by Roald Waldstein to protect the established set of events throughout history and to fix it if it is tampered with. They operate from their field office underneath an archway of the Williamsburg Bridge in New York City in a two-day 'Time Bubble', on September 10 and 11, 2001. Each novel revolves around a major change in the historical timeline and the team must work with each other to fix it with the help of their 'support units' – cyborgs who can mimic human behavior. Later in the series, the characters move to a second base under the Holborn Viaduct in Victorian London.
 
 
 The series follows five protagonists:
 The series also focuses on eight other major and minor characters, some of which are recurring:
 TimeRiders was released on February 4, 2010.
 Liam, Maddy, and Sal, the newly recruited team, are thrown into the thick of it. Before they've had a chance to fully train. Paul Kramer, a brilliant physicist from the future, has plans to alter the past – to lead Nazi Germany to victory over the Allied Forces and to ensure an ordered World Reich under his rule. Liam and the team's support unit, Bob, are sent back in time to try and stop Kramer's plans, whilst in the present, Maddy and Sal witness New York altered by the arrival of a time wave, forming a terrifying new reality – an apocalyptic landscape of ruins and savage mutated descendants of a nuclear holocaust caused by Kramer going insane and detonating some weapon of mass destruction. At the end of the novel Liam and Bob go to Obersalzberg, and stop Kramer from altering history. A firefight ensues, in which Bob is fatally injured, and Kramer & his cohorts die after being killed by the guards stationed outside Obersalzberg. Liam retrieves the AI from inside Bob's head, and returns to 2001 with the timeline restored.
 TimeRiders: Day of the Predator was released on August 5, 2010.
 While Liam and Becks are on a mission to save Edward Chan from an assassin on a school field trip to a zero point energy reactor a time window is accidentally opened to the sixty-five million years ago in the hunting ground of a deadly undiscovered species of predator, and in the process Liam, Becks and a group of college students are sucked in and are trapped there. In an attempt to survive they build a camp and attempt to send messages into the present time, while Maddy and Sal, with the help of the computer Bob try to find them and rescue them.
 TimeRiders: The Doomsday Code was released on February 3, 2011.
 In 1994, Adam Lewis, a British computer hacker finds his name in the Voynich manuscript after decoding a section of it, a code which is almost one thousand years old. He locates and confronts the TimeRiders in 2001, who then travel back to Sherwood Forest in 1194 to discover the origins of the ancient message. But a strange hooded man appears interested in the same thing, and the TimeRiders, realizing that they are in a quest for the holy grail, attempt to find its key, before the hooded man does.
 TimeRiders: The Eternal War was released on July 14, 2011.
 A time wave has struck that alters the entire history of the American Civil War. Abraham Lincoln has followed Liam into the present from 1831 – and now the world is in a dangerous state of limbo. If the TimeRiders can't return Lincoln to the past, the Civil War will never end. Can Maddy persuade two colonels on either side of no man's land to cease fire long enough to save the future?
 TimeRiders: Gates of Rome was released on February 2, 2012.
 Project Exodus – a mission to transport 300 Americans from 2070 to 54AD to overthrow the Roman Empire – has gone catastrophically wrong. Half have arrived seventeen years earlier, during the reign of Caligula. Liam goes to investigate, but when Maddy and Sal attempt to flee a kill-squad sent to hunt down their field office, all of the TimeRiders become trapped in the Roman past. Armed with knowledge of the future, Caligula is now more powerful than ever. But with their field office unmanned – and under threat – how will the TimeRiders make it back to 2001 and put history right?
 TimeRiders: City of Shadows was released on August 2, 2012.
 Hunted by cyborg assassins from the future, the TimeRiders must abandon New York and go on the run. They escape to Victorian London and the streets where Jack the Ripper roams. But, before they can establish their new base, they make their most shattering discovery yet – and it will change everything.
 TimeRiders: The Pirate Kings was released on February 7, 2013.
 Relocated to Victorian London, the TimeRiders joy-ride back to 1666 to witness the Great Fire of London. In the ensuing chaos, Liam and their newest recruit, Rashim, find themselves trapped between the fire and the Thames. They escape on board a river boat, only to be confronted by an unscrupulous captain with his heart set on treasures of the high seas.
 TimeRiders: The Mayan Prophecy was released on August 1, 2013.
 When Maddy finally unlocks fragments of the secret that Becks has been holding on to, the TimeRiders start to piece together their true purpose. Racing through time to connect the clues, the team discover a Mayan tribe where an ancient relic provides a vital link to the past...and future. But not all the TimeRiders can cope with the discovery, and one threatens to bring them all down if they can act out their revenge.
 TimeRiders: The Infinity Cage was released on November 6, 2014.
 The end is approaching for the TimeRiders. In a final effort to prevent time travel destroying history, Liam and Maddy jump forward to 2070 to confront the enigmatic Waldstein and prove once and for all if he is friend or foe. What they discover is more shocking than anyone could have imagined and soon the TimeRiders are on one final mission – back to Biblical times to save the whole of humanity.
 This book ends as Liam is recruited by the caretakers and it is left unknown as to whether Maddy joins him or instead travels to 1994 to be with Adam.