Chief Wiggum dedicates a warning system. Burns is present and makes a joke about the sign not working if the core explodes.

Burns arrives late and collapses due to hypohemia, causing concern.

The doctor explains Burns needs a blood transfusion due to hypohemia. His blood is double O-negative, which is rare. Smithers is not a match, and neither is anyone else at the power plant.

Homer and Marge discuss Bart's blood type. Marge knows everything about her children, including their blood types. Homer is disappointed to learn that he is not a match for Burns.

Homer convinces Bart to donate blood to save Burns' life, promising that Burns will reward them with riches.

Burns sends a thank-you card to Bart, angering Homer who expected a reward.

Homer dictates a nasty letter to Burns, with Bart writing it down.

Homer decides not to mail the letter after Marge's plea, but later discovers Bart already mailed it.

Homer tries to sabotage the mailbox to prevent the letter from being delivered, planning to use a hose to make the ink run.

Mr. Burns reads the letter and is furious, planning to have Homer beaten up.

Mr. Burns plans his revenge on Homer, deciding to crush him.

Mr. Burns talks to Smithers about Homer and the beating. Smithers reveals he called off the beating because Homer saved Mr. Burns' life.

At Moe's Tavern, Moe talks to a customer about Homer's problems and orders a beating on Homer.

Mr. Burns decides to give the Simpsons a gift for Homer saving his life, choosing a book and a crowbar.

The Simpsons react to the gift, with mixed opinions. Homer is disappointed, while the kids are excited.

The family discusses the moral of the story, with different opinions. They eventually conclude that there may be no moral, and that it's just stuff that happened.