Mr. Burns is at death's door and needs a blood transfusion from a donor that has the same very rare blood type that he does. Homer discovers that Bart has the same rare blood type and he sets his sights on receiving a large monetary gift from Mr. Burns, as a thank-you for Bart's blood. Things become interesting when the only thing the Simpson family receives is a simple thank-you card from Mr. Burns.
The Simpsons focuses on a family of five. There is the father, Homer, a dull-witted, alcoholic, lazy, but lovable man. He often gets his family into crazy situations but always manages to fix things. The mother, Marge, is a stay at home mom who keeps the family together. She is the ideal wife and mother though she can be a little naive at times. She always does what she thinks is best for her family.
Next is Bart, the 10 year old boy who lives on playing pranks. He gets into a lot of trouble but is generally a good kid. Then there is the neglected middle child, Lisa. Lisa is the brain of the family and sometimes feels left out because of that. She is an outcast at school because of her talent. Finally there is Maggie the baby. Though she doesn't say much she is well known especially for her red pacifier.