Steel Magnolia is one of three robot outlaws, along with C.H.A.R.L.I.E. and Buck 209 who formed a gang to bust Alloy Roy out of prison and then cause the kinds of trouble robot outlaw gangs usually cause.
After springing Alloy Roy from being imprisoned by Sparks Nevada, Steel Magnolia and the rest of the Alloy Roy Poker Buddies gang discusses how they plan on being both a poker playing club as well as an outlaw gang. Steel Magnolia wins Buck 209's hat as they play.
Alloy Roy and the gang head to rob a space train of unobtainergon cubes, despite their plans being accidentally revealed to all the robot outlaws nearby by Buck 209. They are confronted by Low Down Ralph and his gang, and though C.H.A.R.L.I.E. dies, the remaining three Poker Buddies defeat Ralph's gang.
Buck 209 then turns on Roy, claiming to love Steel Magnolia and doesn't want Roy to have a relationship with her. Magnolia shoots and kills Buck, and agrees to start a relationship with Alloy Roy. The two then head to the space train.
After boarding the space train, in the box they open expecting to find unobtainergon cubes, instead they find Croach the Tracker and Sparks Nevada, who arrest Roy and Magnolia, despite her claiming to not even know Roy to attempt to get out of trouble.