Flush by Carl Hiaasen

A father in jail for taking the law into his own hands. A mother using the dreaded “D” word with her lawyer. A casino boat dumping raw sewage into protected waters—and getting away with it. A mysterious disappearance—possibly murder. How much worse could the outlook be?

When a clever brother and sister, with the aid of an angry waitress, step forward to do their part, everything really gets moving. But it will take a couple of bullies to really do the job in this surprise ending, which just goes to show that “what goes around comes around.”