Key Hunters Series by Eric Luper

Cleo and Evan have a secret. A collection of books so dangerous they are locked up tight. A friend has vanished inside the pages of one of them. It's up to them to find the key that will set her free. A PRICELESS DIAMOND...STOLEN!When Cleo and Evan go undercover to help a rookie detective interview a mansion full of suspects, nothing is as it seems. They must catch the crook -- and find the right key -- or they could be trapped inside this mystery forever...

Cleo and Evan have a secret. A collection of books so dangerous they are locked up tight. A friend has vanished inside the pages of one of them. It's up to them to find the key that will set her free.A SPY MUST BE READY FOR ANYTHING!Agents Cleo and Evan have been given an impossible mission: become super-spies and foil the plans of an evil mastermind. But it won't be easy to break into the Viper's secret underwater lair, complete a daring rescue, find the right key, and get out alive!

Cleo and Evan have a secret. A collection of books so dangerous they are locked up tight. A friend has vanished inside the pages of one of them. It's up to them to find the key that will set her free. THE CURSE OF THE FULL MOON MUST BE BROKEN!On a dark and stormy night, Cleo and Evan are haunted by a disaster. Evan has been bitten by a werewolf! If they can't find the cure -- and the right key -- before the full moon rises, he'll be stuck prowling the pages of this ghost story for good!