Frank and Joe are looking for ways to beat the heat on their summer vacation, so they're super excited about the opening of Bayport's new Splash and Dash Pad. But on their second visit, they find that the fountains are overrun with bubbles! The park director announces that the pad will stay closed until he finds the culprit who poured soap down the drains, so the boys pull out their clue book to search for the Bayport Bubbler.

Were the kids who wanted a bike ramp instead of a splash pad trying to ruin the opening? Or perhaps this is a publicity stunt to promote Lucy Lafferty's new bubble lemonade. The suspects are piling up higher than the bubbles, but if anyone can find the sudsy saboteur, it's the Hardy brothers!