When the family find a stray dog that's been injured, they all decide to nurse it back to health. All, that is, except for Mel, who is violently against them keeping the dog at all. While Lucy christens the dog Dennis and carefully looks after it, Mel makes plans to get rid of it, making posters announcing that they've found a lost dog. At the same time, Josh finds himself in big trouble, having spent the money he raised on a charity sponsored walk. He decides to raise money by running errands, and offers to put Mel's posters up - then makes even more money when he's paid by Lucy to take them down again. Just when Mel and Lucy get over their disagreement and decide to keep Dennis, Josh returns to the house with a 'lost dog' poster from the dog's original owners - and Mel and Lucy have a tough decision to make.