In Paris, Jacques Saunière is pursued through the Louvre's Grand Gallery by albino monk Silas(Paul Bettany), demanding the Priory's clef de voûte or “keystone” Saunière confesses the keystone is kept in the sacristy of Church of Saint-Sulpice “beneath the Rose” before Silas shoots him. At the American University of Paris, Robert Langdon(Tom Hanks), a symbologist who is a guest lecturer on symbols and the sacred feminine, is summoned to the Louvre to view the crime scene. He discovers the dying Saunière has created an intricate display using black light ink and his own body and blood. Captain Bezu Fache(Jean Reno)asks him for his interpretation of the puzzling scene.
Silas calls a mysterious man known as “The Teacher”, revealing that he has killed all four protectors of the keystone and that all confirmed the same location. He dons a metal cilice on his thigh and proceeds to flagellate himself with a whip for the sins of murder Facilitated by Bishop Manuel Aringarosa(Alfred Molina), Silas then travels to Saint-Sulpice and is admitted by an elderly nun; left alone, he excavates beneath the floor of the church to find a stone saying only JOB 38:11, He confronts the nun, who quotes the passage: “Hitherto shalt thou come, but no further,” Realizing that he has been deceived, Silas is enraged and kills the nun.
Sophie Neveu(Audrey Tautou), a cryptologist with the French police, enters the Louvre as well and slips Langdon a message which leads him to the bathroom. There, Sophie meets him and tells him that he is being tracked, a GPS tracking dot has been(unknown by him)slipped into his jacket and that he is a primary suspect in the murder case because of a line of text found by the corpse(“P.S. find Robert Langdon”). Sophie however, believes that Saunière, who is revealed to be her grandfather, wanted to pass a hidden message on to her(Princesse Sophie, P.S., was the nickname he used for her), and that he had wanted to bring Langdon into the equation so that he could help her crack the code.
Buying some time by throwing the tracking device into the back of a truck, the pair begin exploring the Louvre, finding more anagram messages that Saunière had left behind. Many of these relate to Leonardo da Vinci's art, and the pair find a key with a Fleur-de-lis behind Madonna of the Rocks. Langdon deduces from this that Saunière was a member of the Priory of Sion, a secret society associated with the Knights Templar.
Pursued by the French police and cut off from the United States Embassy, the pair escape to the Bois de Boulogne where Langdon closely inspects the key. He notices an inscription on the side — an address. The address directs them to the Depository Bank of Zurich where the key is used for a safety deposit box.
In the bank, they find Saunière's deposit box and open it using the 10 digit Fibonacci numbers in order(1123581321). Inside the box, they find a rosewood container, which contains a cryptex: a cylindrical container with five alphabetical dials which must be arranged in the correct sequence to spell out a 5-letter code word, in order to open and access the papyrus message inside. Using force to open the cryptex would break a vial of vinegar inside, which would dissolve the papyrus and destroy the message.
Unfortunately, the police are called by a security guard and they are forced to leave. The bank manager, Andre Vernet(Jürgen Prochnow), assists them in escaping by taking them as passengers in an armoured van to escape the routine checks of the police. In the back of the truck Langdon and Neveu have a lengthy discussion about the cryptex and Neveu says that her grandfather often played games with her involving cryptexes. Langdon says that the cryptex might hold valuable information or another due about what they are trying to discover. Eventually, they come to a sudden stop and Vernet forces them at gunpoint to give him the cryptex. Langdon tricks Vernet and disarms him and he and Sophie escape with the cryptex in their hands.
Langdon suggests that they visit his friend, Leigh Teabing(Ian McKellen), for assistance to opening the cryptex. Leigh Teabing turns out to be an enthusiastic seeker of the Holy Grail, which he believes is not actually a cup but instead Mary Magdalene. Mary was pregnant at the time of Christ's crucifixion, and Teabing tells Sophie that the Priory of Sion was formed to protect the descendants of Jesus. Jacques Saunière was believed to be a part of this society and Teabing suspects that he was training Sophie to join it also. Silas, meanwhile, breaks into Teabing's mansion and attempts to steal the cryptex. Teabing uses his cane to knock Silas out and they escape again, taking the butler, Remy Jean, and Silas with them. The group escapes in Teabing's plane, following the next clue to London. Fache learns of their destination, and alerts the London Metropolitan Police to apprehend them at the airport. But Teabing manages to slip the party past the police with a trick of misdirection.
Teabing leads Langdon and Nsveu to the Temple Church in London, which is shown to be a red herring. Silas is freed by Remy Jean, who is revealed to be a follower of The Teacher as well. The two take Teabing hostage, and Silas, believing Remy to be The Teacher, holes up in an Opus Dei safehouse. Remy is killed by the mysterious man after deceiving Silas. Silas accidentally shoots Aringaros and is shot by the police. Aringarosa is taken to the hospital and apprehended by Fache.
Langdon is betrayed by Teabing, who is revealed to be the true Teacher. He escapes with the Cryptex, and attempts to find the next clue at Isaac Newton's tomb in Westminster Abbey, as Newton was another member of the Priory. Langdon and Neveau catch up with him, and chase him into the nearby chapter house. Teabing explained that he wanted to find Mary Magdalene's remains to prove he was correct about the Holy Grail and threatens to shoot Sophie if Langdon does not open the cryptex. Langdon throws the cryptex into the air, and Teabing fumbles and destroys it.
Distraught at not receiving the code, Teabing is arrested, but Langdon had cracked the code(“Apple”,a reference to Newton)and removed the clue from the cryptex before destroying it. Using the clue, they travel to Rosslyn Chapel in Scotland where Magdalene's remains had previously been hidden. The remains had since been moved, but they meet other members of the secret organization that protected her. Sophie is actually Magdalene's descendant and therefore is the current living descendant of Jesus Christ. They vow to keep her safe before going their separate ways. In Paris, Langdon accidentally cuts himself while shaving and the line of blood on the sink reminds him of the Rose Line. He follows the Rose Line and finds the location of the Holy Grail, buried under the pyramid in the Louvre. Langdon then kneels above Mary Magdalene's tomb as the Knights Templar did before him.
在巴黎的卢浮宫,白化病僧侣塞拉斯(保罗·贝坦尼饰)逼问雅克·索尼埃拱心石的下落,索尼埃供认拱心石在圣苏比教堂的圣器收藏室里且位于“玫瑰的下面”,随后塞拉斯将其击毙。巴黎美洲大学的符号学和神秘女性学客座讲师、符号学专家罗伯特·兰登(汤姆·汉克斯饰)被邀请到卢浮宫查看犯罪现场。兰登发现索尼埃临死前用黑光墨水、自己的躯体和血摆成了复杂的图形。贝祖·法希警长(让·雷诺饰)请他解释这令人费解的场景。
塞拉斯打给一个名为“老师”的神秘人物,告诉他已经把四名拱心石守护者杀死,四人确认的都是相同的地点。因为犯下谋杀的罪行,塞拉斯在大腿上绑上金属粗布,用鞭子抽打自己。通过曼纽尔·阿林加洛沙主教(阿尔弗雷德·莫里纳饰)的帮助,塞拉斯到达圣苏比教堂,并得到年长修女的认可,让他独自一人活动。他挖开教堂地板,找到一块石头,上面只写着“《约伯记》38章11节”,他找到修女,修女引出原文:“你只可到这里,不可越过。”塞拉斯意识到自己受骗了,愤怒之下把修女杀害。
密码学家索菲·奈芙(奥黛丽·塔图饰)和法国警察一起来到卢浮宫,她塞给兰登一张纸条让他去洗手间,在那里,索菲告诉兰登他被跟踪了,他身上的夹克里被偷偷装进一个GPS定位跟踪器(兰登并不知情),因为警方发现的线索中有一句话“附言:找到罗伯特·兰登”,他现在已被锁定为头号嫌疑犯。而索菲原来是索尼埃的孙女,她相信祖父想将一个秘密信息传递给她(“索菲公主”是祖父给她取的昵称),索尼埃把兰登牵扯进来,是想让他帮助索菲破解密码。
他们花了一些时间把跟踪器扔到一辆卡车后面,便开始在卢浮宫内勘察,两人发现了更多索尼埃用回文构词法留下的信息,多与李奥纳多·达芬奇的作品有关,他们还在油画《岩间圣母》的后面找到带有鸢尾花的钥匙,据此,兰登推测索尼埃是郇山隐修会——一个与圣殿骑士有关的秘密组织——的成员。
两人遭到法国警方的追捕,与美国大使馆切断了联系,逃到布洛浬森林,在那里兰登仔细研究了钥匙,他注意到在钥匙的一面刻有一个地址,地址是在一间苏黎世储蓄银行,钥匙是用来开一个保险盒的。
两人在银行找到索尼埃的保险盒,用十位以斐波纳契数列排序(1123581321)的数字打开了保险盒。保险盒内是一个玫瑰木容器,里面有一个圆柱容器的密码筒,上面是五个按字母排序的刻度盘,肯定是按照正确顺序排列好的五个字符单词的密码,解开后才能取出里面记有重要信息的纸莎草纸。如果用暴力打开会打碎里面的小醋瓶,销毁里面的纸莎草纸和信息,
不幸的是,银行保安报警了,他们被迫离开这里,银行经理安德烈·弗耐特(尤尔根·普洛斯渃饰)协助他们,让他们乔装成乘客坐在装甲小货车后面躲开了警察的检查。在货车后面,兰登和奈芙开始了关于密码筒的长时间讨论,奈芙说祖父以前经常和她玩有关密码筒的游戏,兰登说密码筒的里面应该是有价值的信息或是他们寻找目标的线索。结果,小货车突然刹车,弗耐特用枪指着他们,逼他们交出密码筒,兰登欺骗了他,并把他的枪夺走,和索菲带着密码筒逃走了。
兰登提议去投奔他的朋友雷·提彬(伊恩·麦克莱恩),帮助他们打开密码筒。雷·提彬是个圣杯狂热追随者,他认为圣杯不是个杯子,而是抹大拉的马利亚。马利亚在耶稣被钉十字架的时候怀孕了,提彬告诉索菲,郇山隐修会是为保护耶稣的后代而成立的。有人认为索尼埃是郇山隐修会的一员,提彬怀疑他原是想训练索菲人会的。这时塞拉斯闯入提彬的住宅,试图偷走密码筒。提彬用手杖将塞拉斯敲晕了,随后他们带着男管家雷米·简和塞拉斯坐着提彬的飞机再一次逃走,跟着下一条线索飞往伦敦。法希得知他们的目的地后,提醒他们伦敦警察厅正奉命在机场逮捕他们,提彬设法用错误的指示躲过了警察。
提彬把兰登和索菲带到伦敦圣殿教堂,那是个与目的地不相干的地点。雷米·简其实也是老师的跟随者,他将塞拉斯松绑。两人将提彬作为人质,塞拉斯以为雷米就是“老师”,藏在天主事工会避难所。雷米在欺骗塞拉斯后被神秘人物刺杀,塞拉斯意外射中阿林加洛沙主教,随后被警方击毙。阿林加洛沙主教被送往医院后被法希逮捕。
真正的老师是提彬,他背叛了兰登,带着密码筒逃往威斯敏斯特教堂的艾萨克·牛顿墓寻找下一条线索,因为牛顿也是郇山隐修会的成员。兰登和奈芙赶上了提彬,跟踪他到附近的牧师会礼堂。提彬说他想找到抹大拉的马利亚的尸体,以证实他关于圣杯的猜测是正确的。提彬威胁兰登,如果不把密码筒解开,就把索菲击毙。兰登把密码筒扔向天空,提彬没有接到,密码筒摔坏了。
因未能接到密码筒而心烦意乱的提彬被捕,而兰登其实早已解开密码(“苹果”,与牛顿相关),并且在损毁密码筒之前将线索取出。通过线索,他们前往从前藏匿抹大拉的尸体的苏格兰的罗斯林教堂,遗体已被移走,他们遇到秘密组织的其他保护遗体的成员,他们称索菲就是抹大拉的后代,也就是耶稣基督在世的后代。他们发誓在各奔东西前会保护索菲。回到巴黎,兰登在刮胡子时不小心划伤了自己,水池里的血迹让他想起了玫瑰线,他沿着玫瑰线找到了圣杯所在地,埋藏在卢浮宫的金字塔下。兰登在抹大拉的马利亚墓上跪下,像从前的圣殿骑士一样。