I Am Legend

Is a 2007 American post-apocalyptic science fiction horror film based on the novel of the same name, directed by Francis Lawrence and starring Will Smith, who plays US Army virologist Robert Neville.

The story is set in New York City after a virus, which was originally created to cure cancer, has wiped out most of mankind, leaving Neville as the last human in New York, other than nocturnal mutants. Neville is immune to the virus and he works to develop a cure while defending himself against the hostile mutants.

In 2009, a genetically re-engineered measles virus, originally created as a cure for cancer, turns into a lethal strain which kills 94% of those it infects, mutates 5% into predatory, nocturnal and vampiric mutants called "Darkseekers" who are extremely vulnerable to sunlight and other sources of UV, with only the remaining 1% immune.

Three years after the outbreak, US Army virologist Lieutenant Colonel Robert Neville (Will Smith) lives an isolated life in the deserted ruins of New York City, unsure if any other uninfected humans are left in the world.

The effects of the virus vary in other species; animals that coexist with humans, like rats and domestic dogs, can be infected, but wild animals, like deer and lions, remain unaffected. The city has fallen into ruins and overgrown vegetation covers crumbling buildings; wild deer roam the streets while being preyed upon by lions that have escaped Central Park Zoo.

Neville's daily routine includes experimentation on infected rats to find a cure for the virus and trips through Manhattan to hunt for food and supplies. He also waits each day for a response to his continuous recorded radio broadcasts, which instruct any uninfected survivors to meet him at midday at the South Street Seaport.
Flashbacks reveal that his wife and daughter died in a helicopter accident during the chaotic evacuation of Manhattan, prior to the military-enforced quarantine of the island in 2009, in which Neville stays behind on the island as military personnel.

Neville's loneliness is mitigated by the companionship of his German Shepherd Samantha aka Sam (given to him by his daughter Marley as a puppy to protect him before she died in the helicopter crash), interaction with mannequins he has set up as patrons at a video store, and recordings of old television broadcasts. At night, he barricades himself and Sam inside his heavily fortified Washington Square Park home to hide from the Darkseekers.

One day, while waiting for survivors, Sam follows a deer into a dark building. Neville cautiously goes in after her and finds the deer's corpse along with Sam, but the building is infested by a colony of Darkseekers. Both manage to escape unharmed and the attacking Darkseekers are killed by the sunlight.
Neville finds a promising treatment derived from his own blood, so he sets a snare trap and captures a female Darkseeker from the colony building, while a male Darkseeker tries to go after them, but is blocked by the sunlight and returns to the shadows.

Back in his laboratory in the basement of his house, Neville treats the female without success. The next day, he is ensnared in a trap similar to the one he used to capture the female; by the time he manages to escape, the sun is setting and he is attacked by infected dogs. Neville and Sam manage to kill them, but Sam is bitten in the fight. Neville brings Sam home and injects her with a strand of his serum, but when she shows signs of infection and tries to attack him, Neville is forced to strangle her to death.

Heartbroken and driven over the edge by loneliness by his dog's death, he ventures out and suicidally attacks a group of Darkseekers the next night. He kills a large number of Darkseekers but the rest overwhelm him and he is nearly killed, but is rescued by a pair of immune survivors, Anna and a young boy named Ethan, who have traveled from Maryland after hearing one of his broadcasts. They take the injured Neville back to his home, where Anna explains that they survived the outbreak aboard a Red Cross evacuation ship from São Paulo and are making their way to a survivors' camp in Bethel, Vermont. Neville angrily argues that no such survivors' camp exists.

Neville once again attempts to administer a potential cure to the infected woman in his laboratory, but the next night, a group of Darkseekers, who had followed Anna and Neville back the night before, attacks the house. Neville, Anna, and Ethan retreat into the basement laboratory, sealing themselves in with the female Darkseeker on which Neville has been experimenting. Discovering that the last treatment was successful, Neville tries to assess the situation as the alpha male deliberately
rams himself against a glass door to break in.

Neville draws a vial of blood from the woman he cured and gives it to Anna, before shutting her and Ethan inside a coal chute in the back of the lab. He then takes a grenade and kills the Darkseekers at the cost of his own life, saving the cure. The next day, before dusk, Anna and Ethan discover that her theory is right as they arrive at the survivors camp in Vermont. They are greeted by some military officers and other survivors and Anna is shown handing the cure to a man.

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