Although ten-year-old witch twins Claire and Luna look exactly the same, they are as different as peaches and peanut butter. For example, Claire knows she'll love-love-love summer camp, but Luna is simply dreading it! Fortunately, Grandy, their five-star witch grandmother, has sent Luna off with some magical marigold powder to give her more zest for camp. But when the powder disappears and strange things begin to happen, Claire and Luna worry that there may be a secret rebel witch at Camp Bliss. But how can they do anything about it, when they promised Grandy 'no spells' during camp?