
Bored with her humdrum life, Wendy decides to enlist in the Army. Rex, Bob & Vince join her as well, but Bob and Rex are rejected. Vince on the other hand, has the mental capacities to quickly climb up in the ranks, and is put in charge of monitoring the button that could launch World War III.
Rex arrives home to find that there's a mouse in the kitchen. But this is no ordinary mouse, he is preternaturally strong, extremely aggressive and refuses to be kicked out. The Gang even resort to getting Tiddles the Cat round to sort him out. Then the mouse reveals that he was once Rex's pet mouse, Morris, who Rex sold to Dr Dogg for animal experimentation. A tearful reunion ensues.
Wendy's on heat and the Gang's house is besieged by amorous hounds. The Gang draw down the blinds and prepare to repel borders, but one dog, Handsome Rex catches Wendy's eye and she agrees to go out on a date with him. Vince and Rex insist on chaperoning her. By the end of the evening Rex has made a new friend, Vince has fallen in love with a lobster, Arthur Dustcart's had his underpants cleaned and Wendy's in a very bad mood.