Professor Archibald Chagrijn exposes the world to his blubbering gas, which makes people sad and causes them to cry. Bassie proves immune to the blubbering gas -- as he has had an overdose of laughing gas. The professor is hiding on the Canary Islands, but Bassie and Adriaan manage to track him down.
Bassie and Adriaan find themselves abandoned by their own circus because they overslept, and with no tour-schedule in sight or any money they're forced to take other jobs -- losing each one. A malicious 'poltergeist' turns out responsible for their misery.
