Lost Island was off limits -- until now. Jeff and David are going to the desert island to search for clues. And hidden treasure! Town legend tells of a robber and a secret cave, but the brothers have to piece the truth together. With the help of their cousin, Claire, they'll get to the bottom of the mystery, no matter what they have to dig up.

It's the middle of the night when Jeff spots someone dumping a large bundle into the lake. It's too dark to identify anyone -- or anything. But the cousins immediately suspect foul play, and plunge right into the mystery. Before they know it, the kids of Cabin Creek are in too deep. Everyone is a suspect -- and the cousins are all in danger.

When a rich city kid disappears from nearby Camp Whispering Pines, the three cousins find themselves in the middle of a serious mystery. A ransom note raises the stakes, and the police start tracking down a kidnapper. But Jeff, David, and Claire learn that the boy was last seen headed toward fabled Skull Cliff, possibly in search of its sparkly treasure. The clues just don't add up. As they put all of the evidence together, the cousins start to believe that there never was a kidnapping. But that doesn't mean the boy is out of trouble. He's in more danger than ever.

It's a new school year in Cabin Creek, and the cousins have a new mystery! When Claire and David look out the art room window and see a girl's pale face, they suspect it's a ghost. How else could someone peek through a second-floor window and then just disappear? Rumor has it that the school building was once owned by a rich family, and it has a sad history. As the cousins investigate, they find other peculiar clues: piano music lilting through the halls, a secret passage, and a crooked painting that looks like the ghost's face. Is Cabin Creek's spooky old schoolhouse really a haunted house?

After clearing enough forest to build a log cabin for their new home, Pa returns east to fetch the rest of the family, while young brothers Daniel and Will stay behind to watch the land. Pa had planned to return within six weeks . . . but something must have gone wrong. Now the boys must survive the winter with only a few supplies and their ability to invent and improvise. But are they alone in the woods? Jean Van Leeuwen?s engrossing novel of pioneer survival is based on a true incident.

The cousins discover a stranger sneaking into the local dump. Broken things start disappearing all over town, and then, reappearing, repaired and refurbished.

A thief is on the prowl at Camp Dakota! The campers can't find their favorite things—and they're starting to accuse each other of stealing. The kids set out to find the culprit—but the truth behind the missing stuff may be stranger than anyone expected. Can the campers track down the Cabin Thief? Or will they turn on each other first? Look in the back of the book for experiments and more to help you become a science detective too!