Science Fiction Time Travel

One day, six towers appear on Earth. Each one stands hundreds of stories tall, and are invulnerable to all attacks. At the base of each tower is a portal, welcoming in all who dare enter it. All sorts of magical monsters can be found inside the towers. Even treasure, magic, and superhuman strength can be acquired. The problem is that the towers aren't a friendly place. Even worse, the towers sometimes release waves of monsters to attack Earth. In the year 2083, there are only a hundred survivors. In one last attempt, they challenge the final floor without regard for their lives.

Nyx was born Hollow. An empty vessel in a world of spirits. Normally, that was a death sentence, yet somehow he survived. He's always been stubborn like that. He's also always been a bit crazy. Which is why, in another life, he did something reckless. He sent himself a message—his memories. Threw them into the Flow from which all spirits return. Besides, Nyx believed in asking hard questions. Like, was reincarnation real?

After one death-defying adventure after another, he's ready for some well-deserved downtime. So he's gone to a hot beach in Mareta, a sleepy fishing village in southern Portugal. The year is 1964. He hopes only to flirt with bikinied tourists and drink cold Sagres beers. But two things seem to follow Matt wherever and whenever he goes. A chance to help someone in need, and trouble-trouble-trouble.

Buck and Garth try to retain their humanity as they fight for their lives. How many others can they help? Should they even try? No one knows what's going on except a handful of people and even they aren't sure what happened, but most importantly, how do they stop it? The survivors are rushing to Colorado in an epic race. Time is working against them in more ways than one.

Buck is finally making headway on his journey east. Until he runs into something bigger than all of them. Garth is spinning his wheels. He has a companion who is a great deal of work, but she's also a huge help when he needs it most. Together, they try to dig themselves out of a deep hole. The skies are angry and the time waves are increasing. Nowhere is safe. Except one place and that's not very safe, either. The stakes increase with the struggles as all the players are trying to stay alive long enough to figure it out.

With the defeat of the Overtakers behind them, the five teenagers known as the Kingdom Keepers should be celebrating. By all accounts they saved Disneyland from certain destruction. Why then did their mentor leave one last puzzle for them to decipher? The Keepers must solve a puzzle of the past, or be crushed under an evil that makes the Overtakers seem like gentle souls.

In The Knight at Dawn, Jack and Annie find peacocks for dinner and boys in skirts when the Magic Tree House transports them back to the Middle Ages for another wild adventure. In this second book in the series, inquisitive, notebook-carrying Jack and his animal-charming younger sister, Annie, find themselves in the middle of an enormous castle. They can hear the beginnings of a feast under way in the Great Hall.

The year is 1989. America has just invaded Noriega's Panama. And Specialist Bennett's platoon of Cav Scouts are in country… with, frankly, not a whole lot to do. Until a freak rainstorm somehow transports the entire platoon—Humvees, weapons, and all—to another world. A world controlled by a wicked Aztec god. The Land of the Black Sun. In a heartbeat, the Scouts find themselves fighting for their lives against savage beasts, witches, zombies, subhuman tribes seeking sacrifices… and even themselves.

Almost a year has passed since Stella and Tom discovered a time tunnel and travelled to early 1900s London, where they befriended Emma, Lucy ,and Jack. The magical moles that made the tunnel and secret lake appear have since vanished, but the children are longing to meet again. Then an illness, which puts Emma’s life in danger, changes everything. The moles reappear, just when needed, and Lucy realizes the only hope of finding a cure lies in the future.

Kenna McMillan would do anything for her grandchildren. She would even accompany one of them hundreds of years into the future for a week of Christmas celebrations with the old witch Morna, just to make him smile. But unexpected guests at the inn upend all of their holiday plans. As she learns more about her new acquaintance, she starts to wonder if her week away might take a romantic turn....

Tal has found a doorway to an ancient pocket dimension in the woods, but the discovery has cost him dearly. Spellbook is lost somewhere inside, held by an unknown magical force. Should his bond to the book fade, Tal fears he will lose all awareness of the time loop he’s trapped in and any chance of escaping it. He must get Spellbook back before this happens, but the enchantments protecting the pocket dimension are formidable.

When Hugo and Neve settle in Paris, they assume that they will enjoy a few peaceful years away from the turmoil of British politics, but they are not nearly as safe as they believe themselves to be, especially since everyone has something to hide. Meanwhile, Max must learn to adapt to life on a sugar plantation in Barbados, and decide whether to accept help from an unexpected and dangerous source; a decision which may cost him his life.

A military unit is thrust back into Paleolithic times with only their guns and portable hardware. Ten soldiers on convoy in Afghanistan suddenly find themselves lost in time. Somehow they arrived in Earth's Paleolithic Asia. With no idea how they arrived or how to get back, the shock of the event is severe. They discover groups of the similarly displaced: imperial Romans, Neolithic Europeans, and a small cadre of East Indian peasants.

With each passing day, Kelsea Glynn is growing into her new responsibilities as queen of the Tearling. By stopping the shipments of slaves to the neighboring kingdom of Mortmesne, she crossed the Red Queen, a brutal ruler whose power derives from dark magic, who is sending her fearsome army into the Tearling to take what is hers. And nothing can stop the invasion.

Convicted criminal James Griffin-Mars is no one's hero. In his time, Earth is a toxic, abandoned world, and humans have fled into the outer solar system to survive, eking out a fragile, doomed existence among the other planets and their moons. Those responsible for delaying humanity's demise believe time travel holds the key, and they have identified James, troubled though he is, as one of a select and expendable few ideally suited for the most dangerous job in history.

Stuck between dual realities - charged for a murder he doesn’t recall in one and running from a maniacal billionaire who’s determined to kill him in another - Austin’s monotonous life has become an epic adventure of magic, murder, and political intrigue in both the New Republic of Galiana and the streets of Los Angeles California.

Fourteen-year-old Nephele used to have friends. Well, she had a friend. That friend made the adjustment to high school easily, leaving Nephele behind in the process. And as Nephele looks ahead, all she can see is three very lonely years. Nephele is also a whip-smart lover of math and science, so she makes a plan. Step one: invent time travel. Step two: go back in time, have a do-over of ninth grade, crack the code on making friends, and become beloved and popular. Does it work? Sort of. Nephele does travel through time, but not the way she planned - she’s created a time loop.

Destiny throws her back in time. Can love make her stay? Caroline Sutton doesn’t belong here. Not in the Highlands, and certainly not in the 14th century. Headstrong Caroline hopes an adventure will ease the pain of her parents’ deaths. One minute, she’s standing at the edge of a waterfall, daring her two sisters to jump with her. The next, she wakes up on the shores of a Scottish loch - 600 years in the past. She’s determined to return to her sisters and her own time, but Callum, the rugged Highland Laird who discovers her, has other ideas.

Stranded in the present, time traveler Caleb Hornblower's biggest problem isn't returning to the twenty-third century - but falling head over heels for the beguiling Liberty Stone, who shows him a love more powerful than time itself. Though Caleb knows he belongs in the future, how can he leave the past, and Liberty, behind?

Seventeen-year-old Molly's recurrent nightmares become waking visions after she nearly drowns at a party. Soon she's witnessing events through the eyes of a girl who lived in her father's house nearly a century before.