"Yuruyuri - Happy Go Lily" centers on the daily lives of four middle school girls who revive their school's Amusement Club, a group dedicated to having fun and passing the time. The series primarily takes place at Nanamori Middle School, where the clubroom becomes the focal point for their antics and interactions. The main characters include Akari Akaza, a cheerful but somewhat forgettable girl who often feels overshadowed by her friends; Kyouko Toshinou, the energetic and mischievous leader of the group who frequently comes up with bizarre ideas; Yui Funami, the calm and level-headed member who often acts as the voice of reason; and Chinatsu Yoshikawa, a shy and initially reluctant member who gradually becomes more involved in the group's activities.

The narrative unfolds through a series of episodic, slice-of-life scenarios that highlight the girls' friendships, quirks, and humorous misunderstandings. The Amusement Club's activities range from playing games and reading manga to embarking on small adventures, such as visiting local festivals or exploring the school at night. The series also introduces recurring side characters, including Ayano Sugiura, a classmate with a crush on Kyouko, and the student council members, who occasionally interact with the main group.

While the plot lacks a central overarching storyline, the focus remains on the lighthearted and comedic interactions between the characters. The humor often stems from their exaggerated personalities and the absurd situations they find themselves in, such as Kyouko's over-the-top schemes or Akari's frequent moments of being overlooked. Despite its comedic tone, the series occasionally touches on themes of friendship, self-discovery, and the challenges of adolescence, though these elements are presented in a light and accessible manner.

The setting and pacing contribute to the show's relaxed atmosphere, with most episodes consisting of short, self-contained segments that emphasize the characters' dynamics. The series balances its comedic moments with occasional heartfelt scenes, creating a blend of humor and warmth that defines its appeal. Overall, "Yuruyuri - Happy Go Lily" offers a charming and entertaining portrayal of middle school life, centered on the bonds between its main characters and their shared experiences in the Amusement Club.