It's down and dirty time. Splinter is imprisoned. Leo is dying of poison. Don and Usagi are fighting for their lives and the life of the Daimyo against a horde of assassins.

故事背景设定在美国，生活在贫民区的Angelino与伙伴Vinz，展开了抵抗外星人的冒险故事。

　　以巴克队长为领导核心，小队集结了医生、生物学家、摄像师、机械工程师等7名伙伴。他们是一群活跃在海底的小小冒险家，有着各自的爱好与独一无二的特长，在团队核心巴克队长的带领下向着未知的海域不断探索前进。精致的画面呈现与天马星空的想象力，更增添了动画的观赏性与趣味性。

　　The Octopod is grabbed by a colossal squid. The Octonauts are unable to break free due to the hooks on the ends of the squid's tentacles. Fortunately the arrival of some sperm whales turns the squid from hunter to hunted.

　　Kwazii and Dashi become entangled in a strange deep-sea creature - a siphonophore - and when a geyser blasts it toward the surface, the Octonauts must stop its ascent before it fatally bursts.