There is a new postman in Doggeroo and he doesn't enjoy the local dogs. After Jack tries to play a friendly game with him, the postman accuses Jack of trying to attack him. He also claims to have been bitten by another dog in town. It's up to Jack to clear the good name of the Doggeroo dogs. With the help of Ralf Boxer, a new dog in town, Jack discovers the postman is a victim of nothing more than an overactive imagination. What actually "bit" the postman was a loose nail on a fence.