Boy, Missing — Sophie McKenzie

An adrenaline-fuelled race against time for World Book Day, from the Queen of teen thrillers and author of Girl, Missing, million-copy selling Sophie McKenzie.
 
Cousins Ellen and Harlan have been forced to go on a family camping trip â€" the worst timing ever, because they're in a huge fight. 
So Ellen is happy when Harlan storms off into the woods, but her peace and quiet quickly turns to panic when he doesn't come back.  Facing heart-stopping danger on the clifftops, will Ellen be able to find Harlan before it's too late?