April, Lani and J. D. are on patrol in the scarab, when they notice a boat and suddenly see that two men are knocked into the water by a boom. They go there to rescue them, and the third one is knocked into the water as well. The owner of the boat is named Captain Bob. He is very grateful and tells them that he owes them one. They discover that Captain Bob and his sons are diving for sea urchins, and they earn a lot of money by selling the sea urchins. When Lani and April are talking about the sea urchins in the locker room, J. D. tells them that Captain Bob have agreed to take them with him when he goes diving for sea urchins. They get to keep half of what they catch. When Cody finds out about this, he wants to go too. His car doesn't work anymore and he needs money. Lani decides to tag along even though she has a terrible cold. She can't dive because her ears won't be able to equalize the pressure properly. While they are out looking for sea urchins, they hear a call for help from a ne