Following a car accident on his 81st birthday, ruthless businessman Jack Watson (George Burns) discovers that he's somehow switched bodies with his timid 18-year-old grandson, David (Charlie Schlatter). While David lies comatose in Watson's aging body, Watson has no choice but to adopt his grandson's identity. Thrilled with his newfound youth, Watson soon excels at sports and becomes the most popular kid at school, but with his new lease on life comes a new perspective as well.