Gilligan gets bitten by a bug. From the description, the Professor surmises it is the dreaded Manis-Carni bug. If true, this means Gilligan has 24 hours to live.

He starts showing all the classic symptoms of a Manis-Carni bug bite – aches and pains in the joints, loss of appetite and an itch. The castaways begin an hourly countdown and throw a farewell party for Gilligan.

Then, one by one, everyone else gets bitten by the same bug and are forced to begin their own countdowns.

Luckily the Professor discovers an antidote just in time. Later he learns this particular variety of the Manis-Carni is not poisonous at all and the ‘symptoms’ people were showing were common-day ailments being falsely attributed to the bug bite.