<_< iv'e made a horrible mistake

yeah it is

here’s the basics (incredibly big spoilers for Halo 1, 2 and 3)

Halo 1: The pillar of Autumn (a UNSC ship) escapes a big battle on planet reach by making a blind jump which winds them up to a mysterious Forerunner creation known as a halo ring.
the Master Chief alongside his AI companion Cortana arrive on the world and find the control centre of the ringworld. Master Chief does some exploring and happens to come across the horrific Flood. with the help of a Forerunner AI by the name of 343 Guilty Spark, they locate the activation index to fire the Halo ring to annihilate the Flood. Cortana tells chief that the halo does not kill flood but instead their food, sentient lifeforms. 343 betrays the Chief and Cortana and the two do some other stuff before realising that they could just blow up the crashed ship they arrived on, The Pillar of Autumn. they do so and BOOM, roll credits.

Halo 2: The Covenant find out that the ring has been destroyed and get real ticked off about it (they think Forerunner tech is religious). an elite called Thel Vadam is maimed and forced the rank of Arbiter. meanwhile Chief has to fend off the Covenant on Earth by beating the ever-loving s**t out of them. the covenant flee but are pursued by the Master chief and the rest of the crew aboard the ‘Forward unto Dawn’. chief arrives at some new halo ring and kills one of the three hierarchic of the Covenant (Prophet of Regret) before yolo leaping into a lake because some Covenant carrier nearly space-lazered his ass. Master Chief alongside the Arbiter are dragged away and taken to the head honcho of the Flood: the Gravemind who probably has the best villain voice ever. the Gravemind informs both Chief and the Arbiter that the Ring is a weapon and not a Religious icon which puts Arbiter on Chiefs team. the two fight some Covenant and Flood in a race to prevent the Covenant from firing the ring but is stopped by the Arbiter.

Halo 3: Chief yolo jumps off of a ship that just came from space and lands on earth (cause plot). Chief is reunited with the Arbiter and the two go to a UNSC base known as the Hole. the Prophet of Truth hacks their terminals, spews some nonsense about eradicating all humans and then leaves. Chief and Arbiter go to Voi (some town) to stop Truth from firing something called the Ark. Truth succeeds but instead it was a portal TO the Ark, not the Ark itself. the Flood arrive on Earth and everyone goes through the portal to stop Truth. alot of traveling and Scarab blowing up happens before finally, Arbiter confronts Truth, stabs him and ends the Covenant once and for all. Chief finds there is a half built Halo ring near the Ark and decides to use it to stop the Flood too. he fires it, does the best Warthog section in the series and gets out of there on the ‘Forward unto Dawn’. Arbiter arrives at earth but unfortunately the ship was torn in two leaving Chief stranded in space.