Sherlock Holmes (2009)

In 1890 London, private detective Sherlock Holmes and his partner Dr. John Watson prevent the ritualistic murder of a woman by Lord Henry Blackwood, who has killed five other young women in a similar manner. Inspector Lestrade and the police arrest Blackwood. Three months later, Watson is engaged to Mary Morstan and moving out of 221B Baker Street; while he enjoys their adventures together, Watson looks forward to not having to deal with Holmes' eccentricities. Meanwhile, Blackwood, who claims to have supernatural powers, has been sentenced to death and requests to see Holmes, warning him of three more unstoppable deaths that will cause great changes to the world. Blackwood is subsequently hanged.

Holmes is visited by Irene Adler, a former adversary who asks him to find a missing man named Luke Reordan. After her departure, Holmes follows her as she meets with her secret employer, and only learns that the man is a professor and that he intimidates Adler. Meanwhile, sightings of a living Blackwood and the discovery of his empty tomb convince the authorities that Blackwood has risen from his grave. Reordan is found dead inside Blackwood's coffin. Following a series of clues from the body, Holmes and Watson find Reordan's hideout and discover experiments attempting to merge science with magic. After they survive a battle with Blackwood's men when they try to torch the lab, Holmes is taken to the Temple of the Four Orders, a secret magical fraternity with considerable political influence. The leaders — Lord Chief Justice Sir Thomas Rotheram, U.S. Ambassador Standish, and Home Secretary Lord Coward — ask Holmes to stop Blackwood, a former member of the society and Sir Thomas's secret illegitimate son.

That night, Sir Thomas drowns in his bath as Blackwood watches, and the next night Lord Coward calls a meeting of the Order. He nominates Blackwood to take command in place of Sir Thomas and Blackwood reveals himself to the group, explaining his intention to seize control of the British Empire and reconquer the United States. Standish attempts to shoot Blackwood but bursts into flames when he pulls the trigger of his gun, falling out a window to his death. Lord Coward issues an arrest warrant for Holmes, causing him to go into hiding. Holmes studies the rituals of the Order and recognizes their symbols in Blackwood's staging of the murders; from this, he deduces that the targets of the final murder are every elected member of Parliament. With the aid of Lestrade, Holmes fakes his arrest and is taken to see Coward, where he uses evidence on Coward's clothes to deduce Blackwood has conducted a ceremony in the sewers beneath the Palace of Westminster.

Holmes escapes and he, Watson, and Adler find Blackwood's men in the sewers guarding a device based on Reordan's experiments, designed to release cyanide gas into the Parliament chambers and kill all but Blackwood's supporters, to whom he has secretly given an antidote. Blackwood comes before Parliament and announces their impending deaths, then attempts to activate the cyanide device by remote control; Adler is able to deactivate it with a controlled explosion. Blackwood flees Parliament and sees Holmes chasing Adler, who has taken canisters of cyanide from the device, through the sewers, and pursues both to the top of the incomplete Tower Bridge. Blackwood subdues Adler and fights Holmes, as the latter deduces how all of Blackwood's supposed supernatural feats were the work of science and trickery. Blackwood plummets off the bridge and falls entangled in a noose of chains, the chain wrapping around his neck hanging him for good.

Adler explains to Holmes that her employer is Professor Moriarty, and she warns that Moriarty is not to be underestimated. As Watson moves out of 221B, the police report to him and Holmes that a dead officer was found near Blackwood's device. Moriarty used the confrontations with Adler and Blackwood as a diversion while he took a key component, based on the infant science of radio, from the machine. Holmes looks forward to the new case and his new adversary.