The Bunyip in The Billabong

The newborn lambs are going missing and Matthew thinks the bunyip that lives in a cave under the water in their billabong is taking them. His grandfather told him about it. His mum, dad and big brother say bunyips don't exist, but Matthew is not so sure. He and his grandfather camp out one night to watch the sheep. Matthew sees a dark shape dive into the waterhole. Now he is sure it is the bunyip. His big brother brings home his scuba gear to find out once and for all what Matthew saw diving into the billabong. Will they find the bunyip or will it find them?