The new restaurant in town is a hit, but when several diners get sick, the Health Department threatens to shut the place down. And if the restaurant closes, Todd and Noelle's new friend, JoAnn, may have to move.

Mr. Merlin's Third-Grade Detectives want to prove that the problem wasn't the restaurant's fault. But Mr. Merlin's clue doesn't make any sense -- how can green be dangerous?