The episode opens with Homer and Marge practing for a duet of "Let's Call This Whole Thing Off" for their cousin's wedding. At work, Homer opens a fortune cookies that tells him he'll have good luck. After it proves to be true, Homer passes by a sign for the million dollar lotto and stops in the Kwik-E-Mart. After waiting on a long line to buy the ticket, Homer misses the recepetion, forcing Marge to sing the duet by herself. Homer ends up getting in a car accident on his way, and he wakes up to his family and the news that he won lotto. Unwilling to tell Marge why he missed the reception, Homer has Barney win the lotto in his name and hides in the money in a tree. Homer spends the episode sneaking around buying stuff for the family and letting them accidentally find the gifts. However, when Bart discovers the money, Homer spends some serious cash on Bart, letting him taste the sweet life. When Homer tries to take it away, Bart blackmails his father until he can take it no more. Homer tells Marge on a hot air balloon, and she's just thrilled to have the money... which he just finished spending all of.
Lisa, meanwhile, buy a Zii (Nintendo Wii parody) for Grandpa and his retirement community. When they get too excited, the aides end up putting the Zii in the dishwasher and destroying it to return the old people back to their zombie state.