"Chief of Hearts" is the eighteenth episode of Season 21.
Homer and Chief Wiggum become close friends during Homer's community service stint, but when Homer leaves Wiggum's side during his recuperation to go to Moe's, the Chief takes offense; Bart becomes addicted to Battle Ball (a Japanese game with cards and plastic balls that turn into creatures). Marge believes that Bart is on drugs, because she overhears him saying that they're "addictive and imported."
Homer is outside, walking to the bank while eating a candy apple. When he arrives to the bank, he notices the "No food or drinks" sign outside and attempts to sneak the candy apple inside the bank, but is mistaken for a bank robber in the process.
Homer is soon sentenced to community service, and is forced to clean up trash in a local neighborhood. While on community service, he offers Chief Wiggum a sandwich. Wiggum accepts the offer, and the two quickly become friends.
One night, Homer and Wiggum are out and Wiggum explains to Homer that he has very few friends. Wiggum is soon called on duty when Fat Tony and his gang run into trouble.
Wiggum is shot by one of Fat Tony's men and is soon taken to the hospital. Homer stays by Wiggum's side, but soon grows tired of Wiggum's neediness and decides to go to Moe's.
It's not long before Homer is confronted by Wiggum at Moe's. Wiggum accuses Homer of being a bad friend and wants Eddie and Lou to arrest him, but they can't (since it's not illegal to be a bad friend). Wiggum is livid and storms out and then goes missing.
Later, Eddie and Lou show up to the Simpson house and tell Homer that Wiggum has gone missing. Homer finds Wiggum at the top of a hillside. The two then spot Fat Tony and two of his men with counterfeit Lacoste shirts. Homer and Wiggum are caught and thrown into the trunk of Fat Tony's car.
Wiggum soon finds a way for his and Homer's escape. Wiggum rearranges the CD track in the car, making Janis Ian's "At Seventeen" song play instead of dramatic music that Fat Tony wanted. Homer and Wiggum soon make their escape, arrest Fat Tony and his gang. In the process, Homer and Wiggum also renew their friendship and then proceed to hassle Ned Flanders with a police helicopter.
Meanwhile, Bart becomes addicted to Battle Ball, a Japanese game made up of plastic balls and magnetic cards, and his family and teachers try to help him kick the habit because they think he is on drugs. After finding out it's only a game, Marge finds it cool. Bart gives it up because he thinks that if parents like it, it can't be cool. He then proceeds to flush the pieces down the toilet.