Charlie McCabe and his best friend Lonnie Horowitz had often talked about scuba diving. Now with enough money in their accounts to cover more than expenses, the decision was made. After graduating from their course, the two young men meet an American couple that are just as enthusiastic about diving as they are. Meeting up at the parking lot for access to the beaches at Half Moon Bay and the south end of Wreck Bay, they soon find that someone has a grudge. Why, they don't know, but after the second incident happens, they decide to find out. After they start diving in the bay, they are amazed at their discovery of parts of a sailboat mast. Investigating further they find old boards buried a couple of feet under the mud, on the bottom of the bay. Using the time between tides, they dig at the mud, until they find a hatchway. The excitement grows as they prepare to dive as a group, and discover what may be found inside the old wrecked hull.