Halo 4: Forward Unto Dawn trailer
From Halopedia, the Halo wiki
The scene switches briefly to a number of Single Occupant Exoatmospheric Insertion Vehicles falling through the atmosphere.
Between Mehaffey's lines, the scene switches back and forth to the cadets advancing through gunfire in a forest on an exercise. They take cover.
The scene cuts to a montage of training at Corbulo Academy. General Black addresses a line of cadets.
Scene cuts quickly between the general and Lasky talking to his brother over a video call.
The scene cuts to Lasky walking through the Academy, clearly shunned by his fellow cadets.
The cadets arm their rifles and dress up.
Scene cuts to Silva talking to Lasky outside.
The scene cuts to a mess hall. Vickers roughly shoves past Lasky. Lasky lashes out and the two start fighting.
Cut to Lasky and Silva sitting on a cargo container near the space elevator. Silva examines a note.
Cut to General Black then to Lasky is seen marching past a Warthog, saluting. Scene changes back to Lasky and Silva, who begin to kiss. Their kiss is interrupted by the alarms suddenly going off and the academy's personnel rushing up the stairs.
Lasky and Silva run up to the rest. Several cadets and Marines are seen running down a hallway.
Everyone looks up, seemingly into the sky as lightning strikes.
Explosions pepper the cadets as they run for cover.
Cadets scramble and fall down as explosions continue to pepper. Michael Sullivan speaks into a wall-mounted intercom unit.
The camera cuts around the room frantically. A door is burst from its hinges. A Stealth Sangheili approaches the cadets, creating a ripple in a pool of water. As the cadets cower, an MA5 is heard discharging outside the room and the Sangheili lets out a quick scream. As the cadets cower, John-117 steps through the doorway.
Several cadets are seen running around outside. The shot then changes to Orbital Drop Shock Troopers firing at Covenant forces off screen.
The camera briefly cuts Orenski then to what appears to be Insurrectionist graffiti on a wall. It shows an upward-held fist and the phrase "EX-TERRA". Scenes of combat continue to be shown. Lasky is seen taking cover next to Silva.
The combat continues. Two cadets in battle dress are seen locking hands. Silva, tired, closes her eyes in despair.
The Warthog speeds ahead. More shots of combat are shown.
John and several cadets are seen running as explosions go off around them.
There is a closeup shot of John as he slowly turns his head to face the camera.
OF HALO 4
Lasky runs through a forest.
BEGINS AT DAWN
John jumps from the roof of one of the academy's buildings toward the camera.
HALO 4: FORWARD UNTO DAWN
Cortana's distress signal from the end of the trailer is taken directly from early test audio for Halo 4.