The story is about Byron, a haughty black cat who supports a lonely and depressive writer (Sandra) in delivering all her love to be given. She raises him as she would her own son; they share life together, and then raise Tom, a younger and playful grey kitten. However, as being henceforth old for a cat, Byron gets ill, and given only three months left to live. Sandra must accept the idea of an end; impotent, she has to make the decision to finish whom she loves above all to avoid his suffering.