Lily walks into the kitchen at morning, and as she plays with her toy keys, Rita is about to head off to work to deal with Flip's wisdom teeth having grown back. Before she leaves, she and Lynn Sr. realize that the kids have been good this whole week, and as a reward for their good behavior, they're planning to take them to Aunt Pam's Parlor for ice cream. When Lynn Sr. tells Lily about this trip, she realizes that this could be the perfect opportunity for her to taste ice cream for the first time. However, Lily also hears that if nothing bad happens today, they'll consider taking them out for ice cream.
Later, Lily holds a sibling meeting in order to tell her siblings about wanting her first ice cream, but the siblings are unable to understand what Lily is saying and come to conclusion that she called the meeting just to wave at them. When the siblings leave, Lily discovers numerous toys littered throughout the hallway, and when she hears Lynn Sr. about to come out of the bathroom, she fears that her father will trip. Acting quick, Lily knocks the toys out of the way, and saves Lynn Sr. just in time. Walking into the kitchen, Lily sees Lincoln mopping the floor, when suddenly, Lincoln leaves in order to help Clyde with an emergency. With the floor still wet, Lily proceeds to slide back and forth across the kitchen floor, using her diaper to soak up the water. At that moment, Lily discovers three things happening: Lana and Lola are fighting over the TV remote (Lana wants to watch a penguin show and Lola wants to watch a pageant show), Lynn is about to charge downstairs with a football, and Luan is about to prank someone with a retractable glove. Fearing that these events will harm their mother, Lily quickly uses Charles and Walt's help to avert all three disasters by finding a show about penguin pageants for Lana and Lola, using Luan's prank against Luan, and using the glove to tackle Lynn. Entering the house, Rita announces to the kids that because they were well-behaved this week, they're taking them out for ice cream, much to everyone's, especially Lily's, happiness.
As the family prepares to leave, Lily sees a commercial for Aunt Pam's Parlor and learns that because the parlor wants to give its scoopers more time to relax, they're closing the store at 5:00, which is half an hour from then. Driving off, Lynn Sr. activates the GPS, and says that they should arrive just before 5:00. Suddenly, the family gets caught in a traffic jam, which would delay their arrival. Acting fast, Lily begs to use the phone and successfully finds a shorter route. Unfortunately, they are then pulled over by an officer due to expired registration. Lily prevents them from losing any more time by slinging a block at the kickstand on the officer's motorcycle to send it rolling down the street and the officer runs after it, allowing them to reach their destination just in time. At the parlor, the kids eat their ice cream and Lily begs for a sundae. With her sundae at hand, Lily is about to taste her very first ice cream. Unfortunately, as the family eagerly watches, a bird suddenly swoops down and knocks the sundae out of her hands, causing it to fall to the ground. The family attempts to get another sundae, but the 5:00 closing time has passed. This causes Lily to start wailing in despair and her family immediately feeling sorry for her.
As the family sadly heads back home, Lily discovers Flip's Food & Fuel and begs to go there. When her family is unable to understand what she's saying, she soils her diaper, prompting Rita to turn around. After Lynn Sr. changes Lily, Lily jumps onto the ice cream freezer, giving Lincoln an idea.
The siblings (and Flip, who's still recovering from his wisdom teeth surgery) step in and create a sundae all for Lily, complete with gummy bears, whipped cream, cookie crumbs, chocolate syrup and a cherry on top. With her homemade sundae at hand, Lily finally gets to taste ice cream for the first time. She takes a spoonful, and stuffs it into her mouth, the taste filling Lily to the brim with wonder and excitement. As the family heads back home, Lisa theorizes that Lily had planned this all along and Lynn Sr. believes that she couldn't have done that, since she is just a baby, prompting Lily to give a subtle wink to the viewers.