The story is about a boy who had a bad temper. His father gave him nails and told him to hammer one into the fence every time he lost his temper. Over weeks, as the boy learned to control his anger, he hammered fewer nails each day. Eventually he was able to go a full day without losing his temper. His father then had him remove nails for each day he stayed calm. In the end, all the nails were gone. However, the fence was left scarred with holes, just as hurtful words leave scars. The father explained that saying sorry cannot undo the damage caused by what was said in anger.