The New Adventures of Gilligan

A Sinking Feeling (1x13)

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Mr. Howell hears a story on the radio that leads him to believe lead will soon be more valuable than gold, so he lies to Gilligan to get his help in mining it. Meanwhile, a whaling boat washes ashore, and the rest of the castaways work on getting it seaworthy, unaware that Mr. Howell's lead stockpile will soon ruin their plans.