Halo 5: Guardians is about Master Chief's mourning after the loss of Cortana, beginning a "deeply personal journey" to find answers: "this is about his past and his future."
343 Industries producer Bonny Ross this morning also announced Halo: The Master Chief Collection which will launch on November 11th this year and include Halo 1-4 on a single disc and interface.
Halo 2 Anniversary will include the orginal's multiplayers and you'll be able to swtich between classic and revamped graphics on the fly. The Collection has over 100 multiplayer maps, all of which run on their original engines, at 1080p and there'll be 4000 gamerscore.
Halo Nightfall, Ridley Scott's digital feature, will be included with the Collection. Access to Halo 5: Guardian's beta will also be included.
Halo 5: Guardians is set for release in December 27th, 2014 and will run for one month. The Master Chief Collection's trailer is below.