Kathy is waiting for her mother outside of school when a strange car approaches. The smiling man inside offers to drive Kathy home, suggesting that her mother may be hurt or sick. Just before Kathy is ready to climb in, her mother arrives and the man speeds off. Kathy is confused and hurt that the nice man would leave so quickly.

Later that night, Kathy's parents use examples from nature of pretty but lethal plants and fish to show her that animals and people that look or seem nice may be very dangerous. Not Everyone is Nice teaches children what to do if a stranger approaches and reminds them that looking or acting nice doesn't mean a person is safe.