Philip has invented a cunning space probe to fly up through the ozone hole. Trouble is he needs a cat as passenger but amazingly enough none of his mates will help him out. Meanwhile Zane's bossy sister is very concerned that old Rosie, owner of the local junk shop, is being evicted. To raise money, she decides to hold a spectacular event. Zane and his horrible friends must help her cause But the guys have met Captain Jack, the strange old bloke from volcanic Rangitoto Island, who tells of a famous ancient shipwreck and the lost cargo: muskets enroute to a famous Maori warrior chief in New Zealand. Still there, boys, hidden in a cave on the island. Of course Rangitoto Island is also famous for the legendary giant crabs, but no one believes they're still around. Yeah, right.