The Atlas Corporation found and opened a vault full of powerful alien weapons in the planet Promethea. Atlas then set to look for  the same thing on planet Pandora, but only found relics of the alien civilization from there, leaving the planet and the relics behind.

The Dahl corporation, catching word of this, sent a huge team of archeologists, miners, etc. to check these alien relics, who then settled in Pandora, discovering the potential under its soil and more information about the Vault. As the current season changed, the vast and deadly wildlife of Pandora began to wake up, becoming a major threat for the Dahl corporation, who then left the planet, leaving all of its mining machinery, equipment and employees behind.

The remaining employees left behind that didn't die went insane with time, lacking proper care and education, mutating with various diseases and becoming violent bandits, sociopath cannibals and just insane murderers in general.

After watching her archeology team get eaten alive by Skags, head of the team Tannis discovered more information about the vault as she slowly went insane from social isolation and the constant danger of the planet threatining her from all around. She decides to send word of the vault across the galaxy, under the promisse of unthinkable richies, which draws many interested parties, some decent folk, some not so much.

While most of the so called "vault hunters" either died or gave up pursuing the vault, four of them gathered together after a hiatus, with the help of a man named Marcus, a man of many jobs such as bus driver, scavenger and weapons/ammo seller. If the vault is indeed full of richies, opening it meant that Pandora's marked value (read weaponry) would skyrocket, allowing Marcus greater opportunities to do his favorite thing: earn money. If not for that, Marcus wouldn't care aobut the vault or its hunters, thus, never helping them.

The four Vault Hunters were:

Roland, ex member of the Crimson Lance, Atlas Corporation's militar group, was backstabbed and left for dead by a corrupt superior of Atlas. After seeking revenge and killing said superior, Roland is deemed a traitor and gives up faith on Atlas, setting sets on his own way to search for the said vault full of richies as an opportunity for a new start. He catches a bus by a bus station, which happens to be owned and driven by Marcus, who hears about Roland's intentions and decides to take him to Fyrestone, where he can start his search for the Vault with aid from Dr. Zed.

Lilith, fulfilling her father's last wishes before he was murdered, gets out of that "rock" they lived in, in search for adventure and a better life. Before doing so, a mysterious old woman (also a Siren),  informs Lilith of who she really is (a Siren), and all the dangers and persecution she would suffer because of that. The mysterious Siren also dies, leaving Lilith to wonder and discover on her own about her Siren abilities. Years later, after being harassed inside of a bar in a kidnapping attempt, Lilith meets Marcus, who offers her an opportunity to get out of this constant game of cat and rat. She accepts this opportunity of hunting the richies of a vault and gets into the bus, where she meets Roland.

Mordecai, after being cornered, beaten up and almost killed by one of the many raiding gangs of bandits of Pandora, courtesy of Dahl long ago, wins the fight outnumbered and drags his broken bleeding body across the desert, where he eventually meets with a woman who decides to aid him, but betrays him hours later as she lures him back to the bandits who tried to kill him earlier. In the middle of that travelling, they meet up with Marcus and Scooter, who were fixing the bus that broke down. Marcus offers him a ride, but Mordecai denies since the Bus is broken at the moment. Marcus gives Mordecai his business card and tells him that, whenever he needs a ride and a better chance, he should call him. After taking care of the woman and the bandits with the help of Bloodwing, Mordecai calls Marcus and gets into the bus, where Roland and Lilith were.

Brick was a bandit from another planet, who refused to take part on the kidnapping led by the bandit group he was part of. After not helping them, Brick beats up the gang members and takes the children back to the village from where they were taken from. It is not known how Brick got to meet Marcus, he simply walks into the bus.