Daniel witnesses Chaka, the Unas he previously befriended, being taken captive by a group of human men carrying Goa'uld weaponry and requests that SG-1 investigate. The team encounters a civilization that uses the Unas as slaves, and their attempts to intervene land them in trouble with a ruthless slave owner named Burrock.
"Beast of Burden" provides examples of the following tropes:
- Agony Beam: Burrock uses the Goa'uld cattle prod on both O'Neill and Daniel after taking them captive.
- Born into Slavery: The domesticated Unas on Burrock's planet.
- Full-Circle Revolution: The human population of the planet overthrew the Goa'uld some time ago and promptly started oppressing the Unas in turn, treating them as slaves in much the same way as they were once treated by the Goa'uld.
- Honesty Is the Best Policy: Subverted; Daniel initially suggests that the team see how far honesty gets them when they first arrive on the planet, only to immediately spin a lie about them being traders after Burrock kills an Unas in cold blood right in front of them.O'Neill: Honesty, huh?Daniel: We're traders. We've traded. We trade...
- I Choose to Stay: At the end of the episode, Chaka decides to stay and lead the Unas in revolution rather than return to his home planet.
- I Will Punish Your Friend for Your Failure: Burrock quickly realizes that Daniel cares far more about the Unas than his own wellbeing and instead of threatening him with more torture, promises to kill an Unas for every time Daniel does not give him the information he wants.
- Instant Marksman: Just Squeeze Trigger!: Burrock learns how to use a P90 in a short space of time, and Chaka figures out how to use a staff weapon as soon as he touches it.
- No Good Deed Goes Unpunished: O'Neill and Daniel attempt to rescue Chaka without harming any of the townspeople and get "locked in a madman's barn" for their troubles.
- No One Gets Left Behind: Chaka refuses to go with the team and leave the other Unas behind when they first attempt to rescue him.
- Rescue Reversal: Played with; O'Neill and Daniel get thrown in jail after their first attempt to rescue Chaka fails spectacularly, and at the end of the episode Daniel realizes that Chaka never had any intention of leaving the planet while his fellow Unas were still enslaved and thought he was helping them to escape.
- Schizo Tech: Burrock's people lead a simple agricultural lifestyle and much of their technology is pre-industrial, but they casually use Goa'uld weaponry.
- Sequel Episode: To "The First Ones".
- Slave Brand: All of Burrock's Unas have been branded so that they can be easily identified as his.
- Space Western: The town strongly resembles a stereotypical frontier town, and the townsfolk's treatment of the Unas is a blatant metaphor for how black people were treated in 19th-century America.
- Talking Your Way Out: Discussed and ultimately averted. After the team's attempt to rescue Chaka without taking any human lives fails, O'Neill warns that he doesn't think they'll be able to talk themselves out of this one, to which Daniel replies that for once, he isn't asking them to. O'Neill then authorizes Carter and Teal'c to use lethal force in breaking them out, though they do try to minimize casualties where possible.
- Tastes Like Friendship: Chaka tries to do this with Burrock in The Teaser, offering him the energy bar that Daniel left for him after learning the behaviour from Daniel during their first meeting. It backfires, as Burrock takes the opportunity to zat him and drag him away.
- We Need a Distraction: Carter and Teal'c set off explosives inside the town in order to lure the people away from Burrock's barn so that they can bust O'Neill and Daniel out.
- What Measure Is a Non-Human?: Daniel is outraged at Burrock's treatment of the Unas as they are sentient beings, while Burrock sees them as "beasts" and can't understand why Daniel cares so much. O'Neill sits somewhere between the two, as he is sympathetic to the Unas' plight but asks Daniel whether he is willing to risk human lives in saving them.