Buck 209 is one of three robot outlaws, along with Steel Magnolia and C.H.A.R.L.I.E. 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, Buck 209 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.
Buck 209 accidentally shares Alloy Roy's plans to rob the space train to his address book. Someone in this address book shares the plans to an entire list-serv.
As they near the space train, Alloy Roy threatens to shoot Buck for revealing the plans, but he is talked down by C.H.A.R.L.I.E. and Steel Magnolia. They are then confronted by Low Down Ralph and his gang, who kill C.H.A.R.L.I.E.
Buck, Magnolia, and Roy then kill Ralph and his 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, then agrees to start a relationship with Alloy Roy.