剧情设置在现代巴黎，中法混血的Marinette Dupain-Cheng（玛丽内特·杜平-程）是一个普通的中学女生，性格有些犹疑羞涩，梦想成为时装设计师，暗恋同班的帅气男生Adrien Agreste（阿德里安·阿格里斯特）。当有坏人威胁巴黎时，Marinette化身正义勇敢的英雄Ladybug（瓢虫），搭档爱调戏人的Chat Noir（黑猫），一起打击邪恶势力。但Marinette并不知道面具下的Chat Noir正是她一直不敢表白的男生Adrien，而Adrien也不知道自己的暗恋对象Ladybug却是Marinette。
　　Set in modern-day Paris, the series focuses on a teenage junior high school girl named Marinette Dupain-Cheng and her classmate and crush Adrien Agreste. When evil arises, Marinette becomes a superhero named Ladybug, while Adrien becomes Chat Noir/Cat Noir. Not knowing each other's true identity, the two work together to protect Paris from a villain named Hawk Moth who covets their powers.

　　With time, Marinette and Adrien ended up becoming friends. But the collège girl discovers that declaring her feelings for her friend is not so simple, in fact, it will be almost the opposite!
　　For Ladybug and Cat Noir, despite their new powers and teammates that they can call upon when the situation requires it, the fight with Hawk Moth becomes harder and harder. Their opponent is always stronger as long as he can call on Mayura, a villain who can create allies for the Akumatized, the supervillains.
　　More powers, more action, more villains, and more emotions! Season 3 will put Adrien and Marinette to the test: Will they be able to keep their secret and prevent their private life from interfering with their superhero adventures?

　　Not only is Marinette Ladybug, the superheroine that protects Paris from the attack of villains, but she’s also now the guardian of the Miraculous. This means that not only does she need to keep her identity hidden, but also the existence of these turbulent, magical creatures, the Kwamis! Marinette has a lot of pressure, not to mention her school and love life! Now she has less time and opportunities to tell Adrien her feelings...
　　Marinette now has to redouble efforts to protect her secrets and Ladybug will have to become stronger to face an indomitable adversary: Shadow Moth, who can now fuse the Butterfly and Peacock Miraculous! Thankfully, Ladybug can count on Cat Noir and their new superhero allies!

　　在兔子洞里，灵兔白妮看到时间之窗一个接一个地消失... 未来正在消逝，到底发生了什么？ 同时，马丽娜在家中醒来，发现有人利用奇迹少女与黑猫罗尔的米可幻奇许了愿。 很快，她意识到自己需要变身成奇迹少女……但她发现自己的耳环不见了！ 幸运的是，灵兔白妮在愿望消除一切之前赶来救了她。为了一起拯救未来，灵兔白妮和马丽娜必须找出是谁发现马丽娜就是奇迹少女，以及这个人是何时、如何偷走她的米可幻奇的。 马丽娜意识到蝴蝶米可幻奇现在有了新主人，一切希望似乎都消失了。只有一个人能拯救巴黎和世界，那就是奇迹少女自己。