"Little Busters! EX" is an extension of the original "Little Busters!" anime series, based on the visual novel by Key. The narrative expands on the original story by introducing new characters and exploring their individual arcs, which were not covered in the main series. The setting remains the same, focusing on the lives of a group of friends at a high school who form a close-knit group called the Little Busters.

The series introduces three new main characters: Saya Tokido, Sasami Sasasegawa, and Kanata Futaki. Each character has a distinct storyline that delves into their personal struggles and relationships with the other members of the Little Busters. Saya Tokido is a mysterious girl who claims to be a vampire hunter, and her arc involves uncovering her true identity and the secrets of her past. Sasami Sasasegawa is a cheerful and energetic girl who hides a more complex and troubled side, dealing with family issues and her feelings of inadequacy. Kanata Futaki, a quiet and reserved girl, struggles with her health and the emotional scars left by her family's expectations.

The overarching theme of the series continues to explore friendship, personal growth, and overcoming adversity. The Little Busters, led by Riki Naoe and Rin Natsume, support the new characters as they confront their challenges, reinforcing the bonds within the group. The narrative intertwines these individual arcs with the established dynamics of the original cast, creating a cohesive continuation of the story.

The series maintains the emotional depth and character-driven storytelling characteristic of the original, with a mix of lighthearted moments and poignant drama. The interactions between the characters are central to the plot, highlighting the importance of trust, understanding, and mutual support. "Little Busters! EX" provides additional layers to the world of the Little Busters, offering fans a deeper insight into the lives of both new and familiar characters.