A.G. Riddle books in order

The world’s past and future rests in the hands of five unwitting strangers.

En route to London from New York, Flight 305 suddenly loses power and crash-lands in the English countryside, plunging a group of strangers into a mysterious adventure that will have repercussions for all of humankind.

Struggling to stay alive, the survivors soon realize that the world they’ve crashed in is very different from the one they left. But where are they? Why are they here? And how will they get back home?

Five passengers seem to hold clues about what’s really going on: writer Harper Lane, venture capitalist Nick Stone, German genetic researcher Sabrina Schröder, computer scientist Yul Tan, and Grayson Shaw, the son of a billionaire philanthropist.

As more facts about the crash emerge, it becomes clear that some in this group know more than they’re letting on—answers that will lead Harper and Nick to uncover a far-reaching conspiracy involving their own lives. As they begin to piece together the truth, they discover they have the power to change the future and the past—to save our world...or end it.

A wildly inventive and propulsive adventure full of hairpin twists, Departure is a thrilling tale that weaves together power, ambition, fate, memory, and love, from a bold and visionary talent.  

After a mysterious event, six strangers wake up in an underground bunker.

They don't know how much time has passed. Or where the bunker is located.

They seem to be part of a vast scientific experiment aimed at restarting the human race after a global catastrophe—a program called The Extinction Trials.

What they don't realize is that The Extinction Trials hides a secret.

And so does the world outside.

Control the past. Save the future.

One morning, Dr. Sam Anderson wakes up to find that the woman he loves has been murdered.

For Sam, the horror is only beginning.

He and his daughter are accused of the crime. The evidence is ironclad. They will be convicted.

And so, to ensure his daughter goes free, Sam does what he must: he confesses.

But in the future, murderers aren't sent to prison.

Thanks to a machine Sam helped invent, the world's worst criminals are now sent to the past – approximately 200 million years into the past, to the dawn of the time of the dinosaurs – where they must live out their lives alone, in exile from the human race.

Sam accepts his fate.

But his daughter doesn't.

Adeline Anderson has already lost her mother to a deadly, unfair disease. She can't bear to lose her father as well.

So she sets out on a quest to prove him innocent. And to get him back. People around her insist that both are impossible tasks.

But Adeline doesn't give up. She only works harder.

She soon learns that impossible tasks are her specialty. And that she is made of tougher stuff than she ever imagined.

As she peels back the layers of the mystery that tore her father from this world, Adeline finds more questions than answers. Everyone around her is hiding a secret. But which ones are connected to the murder that exiled her father?

That mystery stretches across the past, present, and future – and leads to a revelation that will change everything.

At CERN, a scientist has just made a discovery that will change the world forever.

Dr Tyson Klein is a quantum physicist working at CERN in Geneva, Switzerland. He is a man completely dedicated to his research, which focuses on finding patterns in the data generated by the Large Hadron Collider (LHC). Thanks to a recent upgrade to the massive machine, Ty believes he's found a new pattern, what looks like an organized data stream, being broadcast over what Ty believes is a sort of quantum radio.

Is it a message sent to us from someone in the future? Or possibly a signal from another universe? Or could the code be something else entirely?

As Ty peels back the layers of his discovery, he quickly learns that what he's found isn't exactly what he thought it was. The code and the message it carries is far more profound – a revelation that will alter our very understanding of human existence and the origins of our universe.

And he's not the only one looking for it. Ty soon discovers that a mysterious organization has been watching him – and following his research – for a long time. And they'll do anything to prevent him from unravelling what is being broadcast by the quantum radio. Because the first one to discover the truth may well control the future.

A hundred miles north of Alaska, a US Coast Guard vessel discovers a sunken submarine at the bottom of the Arctic Ocean. It has no national identification and doesn’t match the records of any known vessel. Deep within, researchers find evidence of a scientific experiment that will rewrite our basic understanding of the human race.

In Atlanta, Dr. Peyton Shaw is awakened by the phone call she has dreaded for years. As the CDC’s leading epidemiologist, she’s among the first responders to outbreaks around the world. It’s a lonely and dangerous job, but it’s her life—and she’s good at it. This time, she may have met her match.

In Kenya, an Ebola-like pathogen has infected two Americans. One lies at death’s door. With the clock ticking, Peyton assembles her team and joins personnel from the Kenyan Ministry of Health and the WHO. What they find in the remote village is beyond their worst fears. As she traces the origin of the pathogen, Peyton begins to believe that there is more to this outbreak—that it may be merely the opening act in a conspiracy with far reaching consequences.

In Berlin, Desmond Hughes awakens in a hotel room with no memory of how he got there or who he is. On the floor, he finds a dead security guard from an international pharmaceutical company. His only clue leads him to Peyton Shaw—a woman who seems to know him, but refuses to tell him how. With the police searching the city for him, Desmond desperately tries to piece together what happened to him. To his shock and horror, he learns that he may be involved in causing the outbreak—and could hold the only key to stopping it.

As the pathogen spreads around the world, Peyton and Desmond race to unravel the conspiracy behind the pandemic—and uncover secrets some want to keep buried. With time running out, they face an unimaginable decision.

A code hidden in the human genome will reveal the ultimate secret of human existence.

And may hold humanity’s only hope of survival.

In 2003, the first human genome was sequenced. It was a breakthrough of historic proportions, but only one scientist knows the full truth of what lies buried in our DNA. That secret will change everything we thought we knew about our past. And our future.

Dr. Paul Kraus has spent his career searching for what he calls humanity’s lost tribes--human ancestors who have gone extinct. When Kraus compares the DNA samples of the lost tribes with our own, he discovers a pattern of changes. A code. He believes he knows what the code is, but the technology doesn’t exist to fully decode it. To protect the secret, Kraus hides his work and disappears.

For years, the secret remains buried. When Kraus dies mysteriously, his work is lost forever.

Now the technology exists to finally unravel the code buried in the human genome. The race to find Kraus’s research has begun, and one group will do anything to find it.

Dr. Peyton Shaw and her mother have obtained part of Kraus’s research--and a cryptic message that could lead to the remaining pieces. They soon learn that finding those pieces may be more dangerous than anyone imagined. But there’s no choice. His work is the key to stopping a global conspiracy--and an event that will change humanity forever.

The ultimate secret, buried in the human genome, will change our very understanding of what it means to be human. For Peyton, finding it may come at an incredible price. She must weigh the lives of strangers against those she loves: Desmond Hughes and her mother. With time running out, Peyton makes a fateful choice--one that can never be undone.

A new ice age...and a shocking discovery...will change humanity forever.

Each month, Earth grows colder.

Snow falls in summer. Glaciers trample cities across North America, Europe, and Asia. The new ice age shows no signs of stopping.

Chaos erupts.

Around the world, people abandon their homes and flock to regions where they can survive. Nations prepare to go to war for the world’s last habitable zones.

Scientists search the cause of the new ice age. They send probes into the solar system to collect readings. Near Mars, a probe finds a mysterious object, drifting toward the Sun. Is it responsible for the new ice age? Or is it merely an observer? Or neither? Could it be a relic from a long-extinct civilization? One thing is certain: investigating the object is humanity’s best hope of survival.

As the ice age claims more lives and the world slides into anarchy, an international consortium launches a mission into space to make contact. But the first contact mission doesn’t go as planned. What the crew discovers out there is beyond anyone’s imagination.

Two members of the first contact mission may hold the keys to humanity’s salvation.

Dr. Emma Matthews is the commander aboard the International Space Station. For months, she has watched the world below freeze and civilization unravel. The headlines tell only half of the story. The messages from her sister tell the rest, of a world witnessing mass migrations, fighting for survival, struggling to provide a future for their children. When a catastrophe strikes the ISS, Emma faces her own fight for survival.

Dr. James Sinclair is one of the greatest scientists alive. A mind before his time. Years ago, he invented something with the potential to change the world—an invention that would upset the balance of power in the world forever. Fearing that change, his enemies sent him to prison for a crime he didn’t commit. But with humanity’s future at stake, NASA asks him to join the first contact mission. His expertise is vital to the mission’s success—and to saving Emma.

We thought the war was over. We were wrong.

After the Long Winter, Emma Matthews and James Sinclair hoped life would get back to normal. They've settled down in Camp Seven and welcomed their first child, a daughter. And they have waited and watched the sky for any signs of the grid's return.

When NASA discovers that several asteroids have broken from the Kuiper Belt and are headed for Earth, James instantly realizes the truth: the grid is back. And this battle will be one to the very end.

As he and his team prepare for humanity's last stand in space and on the ground, Emma makes a discovery closer to home, one that will change life for her and James once again.

With war raging around them, Emma and James fight to keep their family alive. In the cold darkness, humanity splinters. New alliances emerge. At every turn, Emma and James face new dangers--and question whom to trust.

Just when it seems that all hope is lost, James uncovers what may be the key to humanity's survival. But it comes with enormous risks. To implement his plan, he and Emma will have to survive the grid and another, even more deadly enemy. One thing is certain: their gambit will change the future of the human race forever.

The last survivors of the human race escaped a ruined Earth. Eos seemed perfect at first. Warm. Hospitable. Safe from the grid. But everything isn't as it seems.

The planet's first settlers have disappeared. As Dr James Sinclair digs into the mystery of the lost colony, he discovers a series of spheres buried on Eos. Are they the key to finding the lost colonists? Or are they responsible for their deaths? Or are they a sign of something else altogether?

Just as James is unravelling the secrets of the spheres, a storm hits Eos, and in the middle of the chaos, a new danger emerges - a threat no one saw coming...

With time running out to save the colonists, James and Emma will face their hardest choice yet.

The greatest mystery of all time...

the history of human origins...

will be revealed.

In Antarctica, researchers discover a mysterious structure, buried in ice.

In a lab in Jakarta, an autism researcher identifies a revolutionary treatment that could change everything.

But these two incredible discoveries aren’t what they seem. They will set off a race to unravel the deepest secrets of human existence—and an event that could change humanity forever.

A pandemic 70,000 years in the making...will change humanity...forever.

In Marbella, Spain, Dr. Kate Warner awakens to a horrifying reality: the human race stands on the brink of extinction. A pandemic unlike any before it has swept the globe. Nearly a billion people are dead—and those that the Atlantis Plague does not kill, it transforms at the genetic level. A few rapidly evolve. The remainder devolve.

As the world slips into chaos, radical solutions emerge. Industrialized nations offer a miracle drug, Orchid, which they mass produce and distribute to refugee camps around the world. But Orchid is merely a way to buy time. It treats the symptoms of the plague but never cures the disease.

Immari International offers a different approach: do nothing. Let the plague run its course. The Immari envision a world populated by the genetically superior survivors—a new human race, ready to fulfill its destiny.

With control of the world population hanging in the balance, the Orchid Alliance and the Immari descend into open warfare. Now the last hope for humanity is to find a cure. Kate alone holds the key to unraveling the mystery surrounding the Atlantis Plague. The answer may lie in understanding pivotal events in human history—events when the human genome mysteriously changed. 

Her journey takes her across the barren wastelands of Europe and northern Africa, but it is her research into the past that takes her where she never expected to go. She soon discovers that the history of human evolution is not what it seems—and setting it right may require a sacrifice she never imagined.

A mysterious signal from deep space may hold humanity’s last chance of survival.

Northern Morocco: Dr. Kate Warner cured a global pandemic, and she thought she could cure herself. She was wrong. And she was wrong about the scope of the Atlantis conspiracy. Humanity faces a new threat, an enemy beyond imagination. With her own time running out and the utter collapse of human civilization looming, a new hope arrives: a coded message from a potential ally.

Arecibo Observatory: Mary Caldwell has spent her life waiting, watching the stars, looking for signs of intelligent life beyond our world. When that day comes, Mary is thrust into a struggle older than the human race, with far greater stakes. She must decide whom to trust because there is nowhere to hide.

Antarctica: In the wake of the Atlantis Plague, Dorian Sloane finds himself a puppet to Ares and his mysterious agenda. When Dorian moves to take control of the situation, Ares unleashes a cataclysm that changes everything. As the catastrophe circles the globe, Ares reveals the true nature of the threat to humanity, and Dorian agrees to one last mission: find and kill David Vale and Kate Warner. There will be no prisoners this time. The orders are seek and destroy, and Dorian has been promised that his own answers and salvation lie on the other side.

With Dorian in pursuit, Kate, David, and their team race through the ruins of the Atlantean ship left on Earth, across Atlantean science stations throughout the galaxy, and into the past of a mysterious culture whose secrets could save humanity in its darkest hour. With their own lives on the line and time slipping away, Kate, David, and Dorian are put to the ultimate test.