"Dangerous Curves" is the fifth episode of season 20. It originally aired on November 9, 2008. The episode was written by Ian Maxtone-Graham and Billy Kimball while Matthew Faughnan directed it. Maurice LaMarche guest starred as Toucan Sam.
- "When the Simpson family takes a road trip to a cabin in the woods, a series of flashbacks depict Homer and Marge's blissful courtship and their early married years. They recall their first encounter with Flanders and Maude twenty years prior at the very same cabins, where Flanders insisted the unmarried Homer and Marge stay in separates rooms. Later, they recall when they each met distracting members of the opposite sex who nearly wooed Homer and Marge away from each other. Bart and Lisa also reflect on happier times from their early childhood. Despite the obstacles and the passing of time, Homer and Marge attempt to see the forest for the trees."
On the Fourth of July, the Simpson family take a road trip to visit a cabin in the woods. While driving there, they pick up hitchhikers: Squeaky Voiced Teen and his girlfriend, Beatrice. Staring at the two younger teens, Homer flashes back to how he and Marge were, in their dating years.
In their dating years in 1988, a young Homer and Marge are on bikes, riding down the highway. Homer and Marge attempt to kiss while biking, but Homer crashes his and Marge's bike, prompting them to walk on foot, lost. Ned and Maude Flanders, who are driving by, notice them as hitchhikers and pick them up. Ned and Maude shock Homer and Marge by revealing the two of them are married (since 2:00 pm that day); Ned attempts to convince Homer not to have any sexual activities with Marge, much to Homer's discomfort. Back in the present, Homer becomes quite annoyed with the Squeaky Voiced Teen's kissing Beatrice, which prompts him to go into another flashback, in Homer and Marge's married years.
In their married years in 2003, Homer and Marge are more stressed. After Homer is harassed by Patty and Selma, he stops and forces them out of car. Marge says they have the map. When their car runs out of fuel, they head to a nearby home to borrow their phone. The house owner, Alberto, is having a party, and he invites Homer and Marge inside. Wishing to take a break, they accept. Marge then ask Homer about the kids at home and Homer tells her they are being watched by Abe. At their home, Abe was laughing due to being tickled by Bart and Lisa who ask him where his cookies are, he refuses to tell them and they keep tickling them. Marge becomes annoyed with Homer's behavior at the party, and becomes enraged after seeing him flirt with a beautiful woman named Sylvia. After Homer knocks Marge into the pool and starts a sushi fight, Marge regrets marrying Homer. In the present, the family drops off the Squeaky Voiced Teen and Beatrice at a cabin, while the Simpsons head off to their cabin.
Homer and Marge flash back to their dating years again in 1988, where the Flanders' dropped them off at the very same cabin they are at today. Flanders manages to successfully convince Homer and Marge to sleep in separate rooms, much to their disappointment. In their married years again in 2003, Marge leaves Alberto's party with him to run to the cabins. Similarly, Homer runs off with Sylvia to those very same cabins. Not wanting each other to discover their own affairs, Marge hides Alberto in a box and has Homer put it outside; Homer, not knowing Alberto is in there, puts Sylvia inside as well. Alberto and Sylvia fall in love while Homer and Marge rekindle their love. In the present, Homer and Marge meet Alberto and Sylvia, now married with a child of their own, and learn of each other's affairs. Disgusted the most important moment in their early years of marriage was based on lies and deceit, Homer regrets marrying Marge and, trapped in a ball of their luggage which happened while unpacking, has Alberto and Sylvia's child roll him away from Marge into the woods.
Back in their dating years in 1988, Ned tells Homer if he were married to Marge, he could make all the love to her he wants. Ned jokes to Homer saying he has better things to do on his honeymoon than following about two teenagers: the next scene has Ned watching them like a hawk. Taking a walk through the woods with Marge, Homer carves the message "Marge + Homer 4ever" into a tree. In the present, Homer sees this message on the same tree and decides there is still time to save his marriage. He attempts to peel the bark off the tree and show the message to Marge; Marge suddenly arrives to find Homer and accidentally knocks the tree, which had severely weakened roots, over a ravine. Homer clings onto the bark and refuses to let go, but Marge tells him their love for each other is within themselves, not in the bark. Homer falls down the ravine toward the river below, still holding onto the bark and peeling it all off the tree, with Marge falling after. They stop falling when the line of bark stops, allowing them to be saved by Bart and Lisa in their pedal car, which Bart had accidentally driven into the river.