Mark Mylow intends to marry beautiful Julie Mitchell. For his stag night, Mark wants to camp out in the woods under the stars accompanied by his Best Man, Al Large, but it is not long before the two intrepid campers are lost in the woods. Then an adder bites Mark's ankle and he suffers a potentially fatal allergic reaction. Al has finally flown the nest, and has been busy setting up his first home. The flat needs a lot of work to make it habitable again. While he has been wandering in the woods his dad Bert thought he would try to spruce the place up for him, with disastrous consequences. Meanwhile, it appears the beaches of North Cornwall are being stormed by legions of poisonous fish intent on terrorizing the teenage population of Portwenn. Teenage boys have been lining up for treatment for weever fish stings. Martin is furious to hear that the boys had been playing a deadly game of who could stand the pain of being stung the longest.