During the annual manoeuvers, both Bigg City tug fleets service the navy. It is a dangerous job, handling ammunition and explosive barges. All is going smoothly until Bluenose, a bossy naval boat demands immediate priority with a barge-load of gasoline barrels. OJ, the oldest of the Star Tug fleet, warns that it's dangerous to stop the operation half-way through, but Bluenose insists and pushes in roughly. The movement knocks barrels of gasoline off the barge and they split open, spilling their dangerous contents. A spark from Bluenose's stack starts a series of fires and explosions which puts all the tugs in great danger.