Mark has an unusual idea for a stag night, which involves camping under the stars rather than going to the pub. However, the jaunt ends in disaster when he becomes lost in the woods and is bitten by a snake, leaving Martin with the task of locating the clueless copper and saving his marriage before it has even begun. Meanwhile, the teenagers of Portwenn provoke the doctor's wrath by inventing a deadly game that threatens one boy's life.

The tranquility of Portwenn is disturbed when a group of birdwatchers descends on the village in search of a rare bird.