Antisocial misfit Ryohei Arisu wanted nothing more than to leave his mundane life behind, but a wish on a firework transports him to the post-apocalyptic Borderland, a sinister parallel reality where danger lurks around every corner and survival is not guaranteed. To live to fight another day, Ryohei and other unwilling contestants must win a series of games, each deadlier than the last — but returning home means putting not only his skills, but also Ryohei's humanity to the ultimate test.

故事发生在一座与世隔绝的小岛上，在那里，常年居住着守护家园不受侵害的神秘组织，人称“圣灵家族”。作为族长的女儿，菲丽西塔（能登麻美子 配音）一直都接受着严格的教育，但在内心里，菲丽西塔其实和普通少女无异，甚至还有着天然呆的一面。某一日，族长突然做出了举办“圣灵决斗”的决定。这是岛上的古老传统，在决斗中的胜利者，不仅能够成为岛上的统治者，此外，他还会成为菲丽西塔的夫婿。
就这样，个性开朗率真的元气少年利伯塔（福山润 配音），神情严肃野心强大的诺瓦（代永翼 配音），刀子嘴豆付心的戴比特（吉野裕行 配音），这些身怀绝技的男子们接连参加了决斗，究竟谁是最后的王者呢？一切尚在混沌之中。

Four boys named Haruka, Makoto, Nagisa and Rin all participated in a swimming tournament shortly before graduating elementary school and later parted ways. Years later, they reunite when Rin challenges Haruka to a race and wins. Not wanting to be defeated so easily, Haruka gathers Makoto and Nagisa and a new recruit named Rei to form the Iwatobi High School Swimming Club.

Love is blooming at Sakuragaoka High School. Natsuki Enomoto has finally mustered the courage to confess to her childhood friend, Yuu Setoguchi. However, in the final moments of her confession, an embarrassed Natsuki passes it off as a "practice confession." Oblivious to her true feelings and struggling with his own, Yuu promises to support Natsuki in her quest for love. While Natsuki deals with her failed confession, fellow classmate Koyuki Ayase struggles with his own feelings for Natsuki. Despite his timidness, he is determined to win over her heart. This movie follows Natsuki as she dreams of one day ending her practices and genuinely confessing to Yuu. Meanwhile, close friends also find themselves entangled in their own webs of unrequited love and unspoken affections.