At the age of 25, Lucy (played by Scarlett Johansson) lives an ordinary life in Taipei City as an American citizen. However, the deception of love made her a "drug mule" transporting drugs, and behind the scenes was the sinister and cunning Korean Mr. Jang (played by Choi Min-sik). During one transaction, Lucy handed over a box containing a sky-high price of the new drug CPH4 to Mr. Zhang. After witnessing her boyfriend's brutal murder, she herself was imprisoned, and drugs were surgically sewn into her abdomen.
Lucy and three other drug mules are on their way to Europe, however, fate tricks her to suffer heavy losses along the way. As a result of a kick wound to her abdomen, the bag of drugs shattered and seeped into her organs and blood. However, instead of dying, Lucy discovers that she has superpowers that she has never had before. She is able to sense the hearts of others, travel through time and space, and feel no pain when danger strikes. She has become an out-and-out superwoman.
After taking out the drug bag from her body in the hospital, Lucy learned the principle of this drug and felt that her abilities were improving rapidly, she returned to Mr. Zhang's hotel, grabbed him with her superpowers and killed the bodyguard, and obtained information about the location of the other three drug mules from Mr. Zhang's brain. To learn more about the drugs in her body, she contacts Professor Samuel Norman (Morgan Freeman), who may hold the key to keeping Lucy from being killed by drugs.
On the plane, Lucy's physical condition took a turn for the worse. The only way to save her life was to take more CPH4. Meanwhile, Lucy uses her superpowers to remotely control a group of armed police officers and Mr. Zhang's gang members. With the help of Del Leo, Lucy finds the rest of the CPH4. In Professor Norman's lab, Lucy confides in her perception of time and life, and claims that it is human nature that distorts people's perception of the world. Eventually, the remaining three packets of CPH4 were injected into Lucy's body, and her body conjured up a black substance that drifted throughout the lab, eventually forming an invisible, next-generation supercomputer.
She travels back in time and talks to humanity's oldest ancestors. Just then, Mr. Zhang and his men went to the lab and held a gun to Lucy's head. He pressed the trigger, but at this point Lucy's superpower reached 100% and disappeared in an instant. Lucy's voice explains it all: everything in the world is one, and existence can only be proven through time. Lucy vanished, leaving only her clothes and a black supercomputer. At this point, Del Rio rushed to the lab and shot Mr. Zhang. The black computer eventually dissolves to ashes, but Professor Norman retrieves a large, black, flash disk from it. Del Rio's phone received a text message from Lucy saying "I'm everywhere". The movie ends with Lucy's voiceover: "Life was given to us a billion years ago, and now you know what you can do with it".
To be honest, I felt confused after watching the whole movie, and I also felt that I didn't understand it, and then I read a bunch of movie reviews, and found that it was even more unfathomable. I'm just a melon eater, just watch a movie, and I don't have to watch it to understand or something. The professor said to Lucy, I am not sure that human beings are ready to accept this knowledge, this sentence is very good for me, because in history, when knowledge and society are rapidly evolving, there are often violent social upheavals, and new knowledge may not necessarily bring good news, maybe Pandora's box.