When a mysterious letter written in code arrives at King's house for his human, Kayla, he follows the trail of the person who left it.

"Kayla places her tooth in a Tooth Fairy pillow, but it disappears before the Tooth Fairy has a chance to visit--can her dog King help Kayla find the missing tooth?"--Title verso page.

Buddy the dog risks everything when he leaves his new family to investigate what happened to Kayla and her father, his beloved former owners, by slipping into a van Kayla's uncle is using to empty her house in the middle of the night.

When ghost boy Kaz's haunt is torn down and he is separated from his ghost family, he meets a real girl named Claire, who lives above the town library with her parents and her grandmother. Claire has a special ability to see ghosts when other humans cannot and she and Kaz quickly form a friendship. The two join forces to solve the mystery of the ghost that's haunting the library. Could it be one of Kaz's lost family members?

When one of Kayla's library books goes missing, King and Kayla's friend Jillian must help her solve the crime.

Trying to communicate with his human owner (and detective partner) can be frustrating for King the golden retriever as he uncovers clues in a missing dog case.

Dog-and-human detective duo, King and Kayla, must try to figure out how Raj's cat escaped from a locked house.

"Marly, Isla and Sai--now officially known as the Treasure Troop--continue to work on clues from neighbor Mr. Summerling's life, this time investigating mysteries surrounding his house"--WorldCat.

When therapy dog Buddy attends the fourth grade sleepover in the school's library, he solves the mystery of the school ghost.