Sheep becomes a giant because the enlarging ray was not turned off. Major Disaster finds out that apart from Sheep that is destroying the Big City (accidentally) there are disasters coming to the big city. (a flood, a meteor about to collide with earth, and an active volcano) In order to save the Big City they have to make Sheep even bigger using the enlarging ray. Sheep manages to catch the meteorite and puts it on top of the volcano and stops the flood with his wool. Sheep returns to normal because he shrunk in the water.