Eleven-year-old Miri Gill feels left out in her family, which has two sets of twins and her, until she travels back in time to 1935 and discovers Molly, her own lost twin, and brings her back to the present day.

"Rigg's journey comes to an epic and explosive conclusion as everything that has been building up finally comes to pass, and Rigg is forced to put his powers to the test in order to save his world and end the war once and for all"--

Eight-year-old Jack and his younger sister Annie find a magic treehouse, which whisks them back to an ancient time zone where they see live dinosaurs.

The magic tree house whisks Jack and Annie to India during the Mogul Empire in the 1600s to search for an emerald needed to break a magic spell.

Robbed of the powerful object she needed to save her mother, time traveler Etta Spencer is stranded far from home and the privateer she loves before resolving to destroy the astrolabe, a mission that is challenged by a shattering revelation.

Jack and Annie travel back to Victorian London when Merlin asks them to use their magic to inspire Charles Dickens to write "A Christmas Carol."

Jack and Annie travel to Vienna, Austria, in 1762 where they meet the young Wolfgang Amadeus Mozart and his sister and help save the budding genius' life.

When Ms. Information kidnaps the President's daughter, it is up to twelve-year-old Ruby, also known as Pufferfish, to use her super-nanobyte-enhanced allergies in leading the NERDS' investigation.

Seventeen-year-old Prenna, an immigrant who moved to New York when she was twelve, came from another time and she and the other travelers must follow strict rules to avoid destroying the new life they have worked so hard to get, as well as the one person Prenna is desperate to protect.

Ignored by his father and sent to Derbyshire for the weekend, twelve-year-old Peter and his new friend, Kate, are accidentally transported back in time to 1763 England where they are befriended by a reformed cutpurse.