"Soreike! Anpanman Yomigaere Bananajima" is a feature-length anime film based on the popular "Anpanman" franchise, which centers on the adventures of Anpanman, a superhero made of anpan (a sweet bread filled with red bean paste). The story begins with Anpanman and his friends, including Baikinman, Shokupanman, and others, embarking on a journey to Bananajima (Banana Island), a mysterious and vibrant island said to hold a legendary treasure. The island is shrouded in myths and dangers, with its inhabitants facing a crisis caused by the malevolent Banana Ghost, who has cursed the land and its people.

The Banana Ghost's curse has caused the island's bananas, a vital resource for its inhabitants, to vanish, threatening their survival. Anpanman and his friends must uncover the truth behind the curse and restore the island's prosperity. Along the way, they encounter new allies, such as the Banana Princess and her loyal subjects, who are desperate for help. The narrative explores themes of teamwork, courage, and the importance of kindness, as Anpanman uses his powers to protect the innocent and confront the Banana Ghost.

The antagonist, Baikinman, initially appears as a rival seeking the treasure for selfish reasons, but his role evolves as the story progresses. The film balances lighthearted moments with action-packed sequences, as Anpanman and his friends face various challenges, including puzzles, traps, and battles against the Banana Ghost's minions. The climax involves a confrontation with the Banana Ghost, revealing the true nature of the curse and the treasure's significance. Through determination and cooperation, Anpanman and his friends ultimately restore peace to Bananajima, reinforcing the franchise's core message of hope and resilience.