The Chilean painter Javier Marticorena receives an unexpected commission: to portray "Cabezón", an English Mastin. For this he must reluctantly accept that the dog, of immense proportions, spend the night in his small workshop home for a couple of days. In the midst of this unusual coexistence and the difficulties of someone without experience with pets, the making of the painting will not only test the relationship between the artist and the model, but also the human and animal condition.