Shield is a 2012 film written and directed by J. J. Abrams starring Emily Blunt, Asa Butterfield, Emma Thompson, Keith David and Benedict Cumberbatch, among others. The film was scored by John Williams. It was followed by two sequels, Shield 2 and Shield 3.
The film begins in the year 2245, with the UE Anne emerging out of hyperspace after the Dawn of Hope, only to find a huge shield world—a "Shield"—floating in space. Colonel Dana Price (Emily Blunt), a Super Soldier, is aboard the Anne when the ship comes under attack by the Enclave, a religious alliance of aliens and the archenemy of humanity.
With the ship about to be overrun, Captain Helen Jovian (Emma Thompson), the commander of the Anne, orders Dana to protect the ship's droid, Gen (Asa Butterfield). He carries highly sensitive information about the Unified Earth, including the location of Earth, which would prove disastrous if captured by the Enclave. Dana evacuates the doomed ship for the surface of Shield to protect Gen. With the UE Marines and Sergeant Lucas Bishop (Keith David) by her side, Gen providing direction, and her assault rifle ready and loaded, Dana sets out to uncover the mysteries of Shield and fight the Enclave.
After meeting up with surviving UE forces under Sergeant Bishop, Dana participates in a mission to rescue Captain Jovian from the Enclave cruiser Ardent Prayer. After rescuing the Captain, Gen learns that Shield appears to be a site that holds great religious significance to the Enclave. Realizing that the Enclave cannot be allowed to control Shield, Jovian dispatches Dana to secure Shield's control room while she leaves with Bishop to secure a Enclave weapons cache.
With UE Marines as support, Dana leads an assault on the Informatum, a map room which holds information on every location on the world, including the control room. Heading to the shield world's control room, Gen is inserted into the artificial planet's computer system and learns that Shield was made by the Precursors, an ancient alien race that the Enclave worship as gods. However, Gen soon learns that there is something else on Shield, something that terrifies the Enclave. Frightened, he says that Dana has to stop Jovian from accessing the "weapons cache" before it is too late. Dana leaves for the last spot where Captain Jovian and Sergeant Bishop's squad were seen, an underground facility in a swamp. She finds evidence of battle all over the facility, and soon finds a recording of one Marine, which details Jovian's squad encountering a new threat: the Purge.
The Purge is a parasitic species which received their name due to the way they assimilate all resistance with overwhelming numbers. Free for the first time in a hundred thousand years, the Purge sweeps across Shield, devastating Human and Enclave forces alike. The release of the Enclave prompts B1-R3 Prism (voiced by Benedict Cumberbatch), the eccentric droid Supervisor of the shield world, to activate Shield's defense systems. The droid instructs the super soldier to activate Shield by obtaining the Activation Key from the artificial planet's Mausoleum. The Colonel does so, battling hordes of Purge along the way, and returns to the control room. Before Shield initiates its systems, Gen intervenes and tells Dana the truth about the Precursor structure and its purpose- Shield was designed to protect and eliminate the Purge threat by starving the Purge of any life source large enough to sustain them; when fired, it would essentially wipe out all sentient life in the galaxy, safe from the ones in the planet. Realizing the threat of Shield, Gen instructs Dana to detonate the Anne's fusion reactor. This detonation would result in the destruction of Shield, which was against B1-R3 Prism's protocol.
Before doing so, Dana and Gen finds the only survivor safe from them, Sergeant Bishop. The three sabotage three generators needed to power Shield, which buys them enough time to locate Captain Jovian, now succumbed to the Purge, and steal her neural implants to operate the Anne. After battling their way through scattered and disorganized Enclave forces, the spreading Purge, and the Mechanical Guardians under direct command of B1-R3 Prism, Dana and Bishop successfully overloads the ship's engine, and the two and Gen evacuate from Shield in a agricultural ship before the Anne's engine detonates and destroys Shield. The trio appear to be the only survivors, and Dana realizes that they are simply beginning a harrowing battle.
In a post-credit scene, B1-R3 Prism is show to be alive, escaping from the destroyed Shield. He fights his way to an nearby Precursor base, where he meets an expedition team from the Enclave and their leader, Lak (voiced by Robert Davi). Prism reveals to them the truth about Shield, and Lak demands the team to not go back to their base. Lak stands to hear more of Prism's saying, and the screen fades in black.
Emily Blunt as Colonel Dana Price
Asa Butterfield as Gen
Emma Thompson as Captain Helen Jovian
Keith David as Sergeant Lucas Bishop
Benedict Cumberbatch as B1-R3 Prism (Voice)
Robert Davi as Lak (Voice)