Halo 4 is the start of a new saga in the Master Chief's story. This saga is known as the Reclaimer Saga. At the end of the legendary mode of Halo 3 we see Master Chief Petty Officer John-117 orbiting a planet and hear him say to Cortana "Wake me when you need me". Well now is the time to be needed. The game starts where you last left off in a torn in half ship orbiting a planet around four years after the events of Halo 3. John wakes up to Cortana screaming "John I need you!" This creates the beginning of a new saga. In Halo 4 we see a new breed of enemies called the Prometheans. The Prometheans are AIs created by the Forerunners to protect a planet. Unfortunately you're seen as a threat. However despite being made by the Forerunners the Prometheans have a much darker and more sinister plot. Also aside from the Prometheans, Cortana is turning rampant and has begun to turn on the Master Chief. As a new twist, the Master Chief will be working together with the Spartan IV's the ...
Wake Up John.
Did You Know?
Unlike previous games in the series, this game reveals the face of Master Chief, however, his eyes are remained concealed under shadow. See more
It's almost like those Sentinels want us to get the particle cannons offline.
This could be a trap.
You say that like there's a second possibility.