When her best toy mysteriously disappears, Olivia the feisty pig is determined to find out who is responsible.

"Thor's hammer is missing again. The thunder god has a disturbing habit of misplacing his weapon--the mightiest force in the Nine Worlds. But this time the hammer isn't just lost, it has fallen into enemy hands. If Magnus Chase and his friends can't retrieve the hammer quickly, the mortal worlds will be defenseless against an onslaught of giants. Ragnarok will begin. The Nine Worlds will burn. Unfortunately, the only person who can broker a deal for...

"On a class trip to the birdhouse, Pinkalicious discovers that the parakeet has escaped and tries to bring the bird back home"--OCLC.

After a class trip to a floating zoo where animals are mistreated and Savannah's missing pet monkey is found in a cage, Long Island sixth-grader Griffin Bing and his band of misfits plan a rescue.

A tooth goes missing while Pete the Cat is helping the Tooth Fairy, and he must find it before it's too late.

As Nate the Great sets to work on his first international case, he searches for a lost "something" and saves the King of Sweden from a troublesome traveler.

"When ten-year-olds Shirley and Jamila meet, Jamila is simply hoping for a friend in her new neighborhood but Shirley is a detective and together they seek a missing gecko." --

Froggy and his father search the house for the mislaid items they will need on their bike trip.

Nate the Great finds mystery at the beach when Oliver's beach bag vanishes.

At Green Lawn Elementary, the entire school becomes involved in a mystery when Mr. Bones, the skeleton in the nurse's office, disappears.