The narrative centers on Molly, a young girl who has recently transitioned from farm life to a new town. Despite her lack of initial human connections, Molly is surrounded by a charming menagerie of pets: Jumbo, a pig who loves to "dig holes with his nose"; Big Boy, a "very proud" white rooster; Penny, a talented dog capable of performing "tricks"; and Quack, a little yellow duck. These animals serve as her primary source of joy and companionship during her adjustment period.
As Molly integrates into her school life, she begins to form meaningful bonds with her peers. Her social world expands significantly when she receives an invitation to a party at the home of Betty Jane. For Molly, this is a milestone event; she has "never gone to a party before." The excitement is palpable as she rushes home to share the news with her mother, who lovingly promises her "a new dress for your first party," heightening Molly's anticipation for the arrival of Saturday.
On the day of the party, Molly’s excitement is tempered by a practical concern: her pets. As she prepares to leave, the animals gather in the yard, clearly wanting to accompany her. Fearing they might "get lost," Molly follows her mother’s advice to "shut them up in the garage." With a heavy heart, she bids them farewell, promising to return soon. Molly sets off toward Betty Jane’s house, feeling "proud" and holding her "head very high" in her new dress, unaware of the impending disruption.
Upon arriving near the party, Molly notices the other children suddenly stop playing and laugh. Overcome by insecurity, she wonders, "I wish I had never come" and worries that her "new dress looks strange." The mystery is solved when she hears a noise behind her and discovers her pets have escaped. Jumbo had utilized his natural talent to "dig holes" in the ground beneath the garage, creating an exit for himself and his cohorts. Penny had led the group by going "sniff, sniff along the ground" after Molly, with the others trailing behind in a comical procession.
Initially, Molly is "angry at her pets," commanding them to "go right back home." However, the atmosphere shifts when Betty Jane intervenes, encouraging Molly to "let them come to the party too." The other children join in, welcoming the animals with enthusiasm. The party transforms into a delightful experience where Penny showcases his "funny tricks," and the pets even share in the "ice cream and cake."
Ultimately, the event becomes more than just a social gathering for Molly; it becomes a shared memory between her and her animals. When she returns home, she tells her mother about the "best time," proudly declaring that "all five of us"—herself and her four loyal pets—attended the party together. This story highlights the themes of childhood innocence, the unpredictability of life, and the heartwarming bond between a girl and her loyal companions.