A piranha fish is wrongly delivered to Figaro's house. A fearful Figaro causes the fishbowl to shatter, leaving the fish gasping for life.
Filled with remorse, Figaro turns on the taps in a desperate attempt to save the fish. In so doing, this fills his house with water. Instead of being grateful, the fish becomes a monster with an unquenchable appetite for revenge. Figaro and Rivet are plunged into a deep-sea adventure, which ends with them cornered in Figaro's toilet.
The toothy terror is about to devour them when a simple pull of the toilet chain brings an unexpected end to the danger.