Despite Bassie and Adriaan's jokes, more and more people are crying. This crying is caused by a disturbed professor, Archibald Chagrin, who wants to make the whole world cry with his griengas. He's gone crazy in an accident with one of his gases, and now he's under the delusion that laughing is a waste of energy. When Bassie and Adriaan catch Joris, the professor's accomplice, at their caravan one day, they devise a plan with the police to track down the professor. However, the plan does not go without a fight and the clown and acrobat soon find out that it is going to be an exciting adventure.