Twelve-year-old Héctor Muñoz, fleeing from bullies, discovers a magical closet that not only provides him sanctuary, but also unites him with two other kids facing similar problems at their own schools, helping them find friendship and strength in each other.

When a medieval princess appears out of a rusty box bought at a yard sale, fourteen-year-old tomboy Casey Peabody and her family are stuck with her royal snobbiness until the young wizard who had trapped her there figures out the spell to send her home.

When Jonah and Katherine travel to early 1900s Switzerland and Serbia to return Albert Einstein's daughter, Lieserl, to history, her mother Mileva grasps entirely too much about time travel and has no intention of letting her daughter go.

When Albie's mother dies from cancer, his father explains that she may be alive in a parallel universe, so he decides to universe-hop and find her with the help of a banana, a laptop, and a box.

After mastering the ability to walk between dimensions, sixteen-year-old Joey Harker and his fellow InterWorld freedom fighters embark on a mission to maintain peace between the rival powers of magic and science who seek to control all worlds.

Eleven-year-old orphan Tommy Learner's world in 1900 New York City collides with that of twelve-year-old, modern-day Jezebel Lemon in the basement of her apartment building, where together they must use the portals between worlds to thwart the Dead Gentleman, a legendary villain whose last unconquered world is the planet Earth.

Four cousins, Roger, Ann, Eliza, and Jack, have an extraordinary summer when, after an old toy soldier comes to life, they find themselves transported back to the days of Robin Hood and Ivanhoe.

Connecticut middle-schooler Jake and his older sister Kady are transported by a Mayan artifact to a strange world inhabited by a mix of people from long-lost civilizations who are threatened by prehistoric creatures and an evil alchemist, the Skull King.

Emma had the perfect trifecta: good job, steady boyfriend, creative best friend. However, after one crackling, long-distance phone call, her world changed forever. Now she's having nightmares that threaten to disrupt the space-time continuum. But these nightmares, featuring a young girl named Lily, seem all too real, and Emma's waking life begins to be affected by the events that transpire in this mysterious wartime landscape. Sara Goudarzi navigates...

As a realm walker, young Cantor D'Ahma has the ability to cross between worlds in the service of the good and the right, and with his Mor Dragon and best friends Bixby and Dukmee he sets out to determine just what those good things are as they learn that nothing is quite what it seems.