This wartime documentary from the Canada Carries On series explains the importance of the motor torpedo boats of the Royal Canadian Navy. Narrator Lorne Greene describes the fast, heavily armed boats. Explaining that they are only seventy feet long, he points out that the MTB's are able to challenge much larger enemy ships. Their crews, made up of young navy men from all over Canada, maintain them in constant readiness for the job of protecting Allied shipping routes. We see "Canada's Fighting Sea Fleas" in action against German E Boats.