For Julio, taking the dogs of his neighbourhood out for walks is a difficult task, above all because he simply detests dogs. Nevertheless, he is also aware of the great advantages of earning a little extra money in this way, such as being able to buy a fantastic computer. When one day Julio’s parents go off on holiday, they leave the boy in charge of his aunt Pilar. All that Julio wants to do, however, is to stay at home on his own and finish programming the “virtual universe” he is creating on his computer. As soon as he manages to get rid of his aunt, he breathes a sigh of relief: his plan is underway at last. But in the middle of the night he is awoken by some strange noises... And he is possessed by fear.