Once inside, he not only discovers the hidden chamber, but recovers crucial information and a bracelet device from the remains of what might have been Earth's last Sirian. From the riddles uncovered from the hierogylphs, Sam detonates the Sphinx with explosives, revealing a tunnel underneath the Sphinx and descends into the pyramid. Sam clears himself to the pyramid and makes it to the Sphinx. The scientists at HQ decipher the hieroglyphics which indicates a hidden Sirian chamber below the Great Pyramid of Giza. He makes it into the museum, recovers the data from Stein's phone and transmits it to headquarters. Sam's insertion goes haywire after his helicopter is shot down and both teams are quickly wiped out, leaving Sam the only survivor. Sam tells his squad they are are protecting professor Stein, a scientist carrying hieroglyphics believed to contain instructions for powering up the Time-Lock. Their mission is to recon with Bravo Team after they lose contact with HQ. Sam 'Serious' Stone, Captain of the Earth Defense Force, is dispatched with a small squad of soldiers to Cairo in Egypt, which has been occupied by Mental's alien army for sometime. But as the device lies dormant, they must first discover a means to turn it on. Through it, that person could reach a pivotal point in time and assassinate Mental in the past and change the future for humanity. In a last-ditch effort, the survivors turn to the Time-Lock, a recently excavated device that, allegedly, is capable of granting a single person the ability of time travel via an inter-dimensional portal. This leads to a three year-long war that has driven humanity almost to the point of extinction. During this time, Mental, an extraterrestrial overlord, is awakened from dormancy by the humans and sends out his hostile alien armies to attack Earth.

In the middle of the 21st century, humanity had begun to uncover artifacts and ruins left behind in ancient times by the Sirians, a long forgotten alien race from the planet Sirius. Team Alpha in a Black Hawk, on their way to the museum.

Serious sam 3 weapons