Paco, a young drug addict, recently mourning the death of his best friend from a heroin overdose, is unable to overcome his addiction on his own. Withdrawal is too painful for Paco, who is under the watchful eye of his severe but concerned widower father, Evaristo Torrecuadrada, a civil guard commandant. To find a detox treatment for Paco, father and son move to Madrid. They are welcome in the household of Paco's feisty grandmother who lives with her faithful old maid, Adela. Both women naively believe that Paco ailment is diabetes completely unaware of his drug addiction.