"Mason and Ty were once the very best of friends, like two nerdy sides of the same coin...until seventh grade, when Ava Petrakis came along. Now Mason can trace everything bad in his life to that terrible fight they had over the new girl. The one thing he'd give anything for is a do-over. But that can't happen in real life--can it? As a science kid, Mason knows do-overs are impossible, so he can't believe it when he wakes up from a freak accident...

Molly Moon, reunited with her parents, is hypnotized by a mysterious turbaned gardener and eventually transported to India, where she meets not only a maharajah with a speech defect but also former versions of herself.

Two very hungry dinosaurs discover a time machine and are instantly transported to America in 2018, where they are delighted to find themselves surrounded by food (including pizza and doughnuts), but soon less excited to find themselves surrounded by policemen with guns--so they escape to the time machine, not knowing where it will take them next.

After purchasing a time machine at a garage sale for three dollars, Liam uses it to summon Thomas Edison for help with his book report, but when a different Thomas Edison from the 1930s arrives, hilarity ensues.

George and Harold are forced to contemplate a world without Captain Underpants.

Molly Moon's hypnotic eyes give her the power to stop the world and travel through time. Now Molly makes a stunning new discovery - she's a mind reader! But can her incredible talents help to rescue her lost twin from future? And will Molly be a match for the maniacal Princess Fang and her crazy mind machine?

"Herbert, Alex, and Sammie are pretty sure their adventures in the future are over until they meet their greatest villain yet: Sammie's future self, AeroStar, a power-mad tyrant who wants revenge. It's up to our heroes to once again don the mantle of the AlienSlayers and somehow try to save the past, present, and the future from total annihilation"-- Provided by publisher.

When pirate cats threaten Mouse Island, Professor von Volt sends Geronimo Stilton and his friends back through time to ancient Greece, Atlantis, and Stonehenge to try and find out how ancient civilizations were able to find peace and avoid war--only to find that the key to peace was under their whiskers the whole time.

What seems to Mike Evans like a boring dinosaur dig in China turns suddenly dangerous when he finds evidence of a live dinosaur in the neighborhood--and he and his friend Shannon run into a villain in a skull mask called Mr. Bones who is controlling both a feathered dino, and a fierce carnivore.

Michael Evans is in Montana on a dinosaur dig with his paleontologist father, but he certainly never expected to find a live Tyrannosaurus Rex plucked out of its own time and looking for dinner, nor encounter a girl with some very advanced technology trying to trap the beast.