AC 188: Assassin Odin Lowe and his young ward, an eight-year-old boy with shaggy dark brown hair and Prussian-blue eyes, arrive on L3 X18999 - the colony is still under construction, approximately a year from completion. Odin tells his junior partner that this is the last assignment he'll be taking. (Dekim Barton has hired Odin to assassinate Brigadier General Septum... Septum was the one who hired Odin years earlier to assassinate Colony Leader Heero Yuy.) He also tells the boy that he expects him to disappear into the chaos of the coming coup and settle down, go to school on the new colony.
Later the two sit on top of a building watching the coup d'etat unfold before them. Colony rebels, lead by Quinze, have seized eight Tragos suits and are attacking the central command center of the colony. Odin imparts one final piece of advice to his young ward before the two separate. He tells the boy that he should live by his feelings and not regret things after the fact, that it's the 'right way' to live the moment to the fullest. The two then part ways.
The boy heads off into the midst of battling Tragos and Aires suits armed with a rocket launcher. He fires at the command center but the shot is blocked by a mobile suit (piloted by a young Treize Kushrenada). Meanwhile, Odin hunts down Septum, but the assassination attempt fails and he switches to his backup plan, wiring the base's armory with explosives. Dekim Barton confronts Odin and shoots him before the assassin can detonate the charges.
The boy finds Odin rapidly bleeding to death and the assassin reminds Heero to act on his emotions. Odin dies and the boy picks up the detonator and sets off explosions around the command center. He then follows his instructions, disappearing into the chaos. An indeterminate time later, the boy, now in his familiar black spandex and green tank top, wanders around the colony and comes across Dr J sitting in an alley. The scientist says he likes the look in the boy's Prussian-blue eyes and asks if he wants to pilot a gundam. The boy thinks back on Odin's parting advice to act on his feelings and says yes.
AC 194: The boy who will later be known to us as Heero Yuy has been operating/training under Dr. J for the past six years. He is given a sabotage mission: to blow up an Alliance base (in the L1 colony cluster presumably). He jumps a chain link fence, runs and flips over onto his back laughing like any fourteen-year-old boy might do on a bright sunny day. A little girl and her puppy approach the youth and she asks if he is lost. The boy tells her he's been lost since the day he was born. The girl gives him a flower and goes on her way.
Later that night, the boy completes his mission, setting off explosions around the Alliance base, however - due to either a miscalculation or simple misfortune - a mobile suit falls into a civilian housing complex killing several people, including the little girl and her puppy. The grief-stricken/guilt ridden boy carries the dead puppy back to the rebel compound where he buries it, marking the grave with two stones stacked on top of one another. Learning of this, Dekim Barton (Operation Meteor's mastermind and probable financial backer) demands the boy be retrained at once to eliminate such unnecessary human feelings as kindness.
AC 195, April 6: Dr. J tells his ward that the Barton Conglomerate plans to assassinate Vice Foreign Minister Darlian at the Fifth Colony Summit at the L1 colony cluster. He gives the young man three choices: 1) cooperate with the Barton Conglomerate and assassinate the Vice Foreign Minister, 2) stop the assassination and protect the Vice Foreign Minister or 3) ignore the mission. He chooses option two, taking out the assassin on a rooftop overlooking the conference center.
Meanwhile, back at the rebel base, an assistant brings Dr. J an astro suit (the one Heero wears in episode 1) pointing out the self-destruct device that's been linked to Wing Gundam's self-destruct mechanism. Dr. J tells the assistant to modify the priming frequency on the gundam so the astro suit will misfire.
Later that day or the next (time frame unclear), the young man we know as Heero kneels down, setting a flower on the puppy's grave. He stands there for a moment lost in thought and then pulls out his automatic, chambers a round and presses the barrel to his temple. Dr. J walks up behind him with one final mission, saying he's decided to go through with Operation Meteor. ("Operation Meteor" is planned by Dekim Barton and coordinated by Quinze. The objective of which is to drop a colony on the Earth and then send the five Gundams to seize control of the crippled planet.) Dr. J once again gives his ward three choices: 1) pilot the gundam and commit mass murder, 2) shoot Dr. J and run or 3)... (neither J nor Heero speak the words aloud so we are left to use our imaginations).
AC 195, April 7: The young man sits in the cockpit of Wing Gundam, apparently waiting for take off clearance. A brief conversation with Dr. J indicates that Heero has chosen an altered form of Operation Meteor as his mission. Dr. J gives him the code name Heero Yuy. The shuttle carrying Wing Gundam launches toward Earth... thus begins Episode 1 of the series.