Beloved lunch lady Diana Dumpling has suddenly vanished. Can Mariella and the Mystery Girls solve this kitchen nightmare?

After Mickey witnesses his father's death and his mother's admission into rehab, he is sent to live with his estranged uncle and change high schools, but when Mickey's new girlfriend, Ashley, suddenly disappears Mickey refuses to let another person walk out of his life and follows clues that reveal truths about both Ashley and Mickey's father.

In nineteenth-century England, after her father's disappearance Nan Sparrow, ten, works as a "climbing boy," aiding chimney sweeps, but when her most treasured possessions end up in a fireplace, she unwittingly creates a golem.

"Eleven-year-old Riley's mom has disappeared and Riley knows that if he leaves tributes for the whispers, magical fairies that grant wishes, his mom will come back to him"--

One month before graduating from his Central Florida high school, Quentin "Q" Jacobsen basks in the predictable boringness of his life until the beautiful and exciting Margo Roth Spiegelman, Q's neighbor and classmate, takes him on a midnight adventure and then mysteriously disappears.

The harrowing tale of survival and suspicion takes its most dramatic turn yet when Molly, Yoshi, and the rest discover that there are more than just monsters in the rift.

On the eve of the first manned space mission to Mars, Secret Agent Jack Stalwart learns that chief rocket engineer has disappeared, then finds out the engineer is his father. He then vows to do what it takes to make the alleged kidnapper sorry for his act.

"Forty years after a devastating flood changed the face of the earth, new consequences and challenges are still surfacing. Twins Will and Annalie thought the hardest part about this year was going to be their separation when bookish Annalie began life at a prestigious Admiralty-run boarding school and avid sailor Will stayed behind in the flood-damaged slums. But that was before ... their father disappeared, leaving a single coded clue to his destination....

"One hundred and fifty years ago, the first dinosaurs were cloned. Soon after, they replaced humans at the top of the food chain. The only way to survive was to move into underground compounds. . . . Five years ago, Sky Mundy's father vanished from North Compound without a trace. Now she has just stumbled on a clue that not only suggests his disappearance is just the tip of an even larger mystery, but also points directly to the surface. To find her...