"The Ori just want to use us, and killing in their name is not self-defense. It's murder."
— Jared Kane
Jared Kane seeks assistance from Earth after a Prior visits his planet and helps his government build a Kill Sat with which to destroy their rival nation, the Caledonian Federation. The team takes the Prometheus with the intention of destroying the satellite, but the plan is compromised when Daniel and Kane are taken as political prisoners after their attempts to negotiate with the Rand government fail.
"Ethon" provides examples of the following tropes:
- Bus Crash: Kane reveals that his wife Leda, who developed a close relationship with Daniel while he was stranded on Tegalus, succumbed to a Prior plague and died several months ago.
- Call-Back: Mitchell repeats O'Neill's line from "Icon" about sticking their noses where they don't belong every time they go through the gate.
- Continuity Nod:
- Daniel points out that Tegalus would not be in the mess it is currently if the team had never gone there in the first place.
- Carter states that she realized the F-302s gave off an electromagnetic pulse on destruction following the battle of Antarctica.
- Continuous Decompression: Several Prometheus crew members are seen getting sucked out of a window after the hull is breached following the first hit from the satellite.
- Death Notification: Mitchell states at the end of the episode that he personally delivered the letter to Col. Pendergast's family.
- Determinator: Daniel comments on his own total inability to accept defeat after the Prometheus is destroyed while he and Kane are imprisoned on charges of treason:Kane: Do you ever give up?Daniel: Not until I'm dead... and sometimes not even then.
- Downer Ending: The episode ends with Daniel and Mitchell sullenly sharing cans of cheap beer following the revelation that Rand and Caledonia ended up destroying each other despite their best efforts, meaning that the loss of the Prometheus was in vain.
- Drowning My Sorrows: Mitchell pops open a can of cheap beer, hands it to Daniel, and opens one for himself. Mitchell tries to be Mr. Exposition, but all he and Daniel say boils down to "Rough day."
- Explosions in Space: When the Prometheus is destroyed.
- Foreshadowing: The Rand satellite's Curb-Stomp Battle of Prometheus foreshadows how easily the Ori will destroy Earth, Goa'uld, and Asgard ships.
- Going Down with the Ship: Pendergast chooses to stay on the bridge as the Prometheus is blowing up around him to oversee the evacuation of the crew.
- Kill Sat: Kane reveals that the Ori have supplied one to the Rand government and asks for the team's help in destroying it before it can be used against Caledonia. Unfortunately things don't quite go according to plan, and the satellite is used to take down the Prometheus instead.
- Killed Off for Real: Colonel Lionel Pendergast, commander of the Prometheus.
- Know When to Fold 'Em: Pendergast tries to surrender to the Rand government after the Prometheus is badly damaged from the satellite's first attack. President Nadal isn't having it, however, and fires again, destroying the ship.
- Mauve Shirt: Kevin Marks, pilot and weapons officer on the Prometheus, survives this episode and goes on to pilot every subsequent American hyperdrive-equipped ship across all three series and a movie without ever rising above the status of minor recurring character.
- Narrow Annihilation Escape: Even after the Caledonians agree to a ceasefire, a fight breaks out in the Rand command center, and tensions are later implied to have boiled over into an all-out war. The SGC is unable to later dial into Tegalus' Stargate, and it's again implied that the planet destroyed itself in mutually-assured destruction.
- Nice Job Breaking It, Hero: Daniel and Kane both state at various points that they are at least partially responsible for the current political situation on Tegalus due to their actions in "Icon".
- Sacrificial Lion: The Prometheus.
- Sadistic Choice: Mitchell and Carter are faced with the choice of either destroying the satellite while Daniel is still being held as a political prisoner in Rand and potentially losing any chance to negotiate for his release, or aborting the mission to take out the satellite and endangering the citizens of Caledonia. Carter eventually points out that Daniel wouldn't want them to potentially sacrifice thousands of innocent lives for him, but their initial hesitation has some very dire consequences.
- Sanity Slippage: President Nadal, who is incredibly paranoid about Caledonian spies and has been completely taken in by the Ori. It gets to the point where he's eventually killed by his own second-in-command after violating an international treaty that had been agreed on seconds beforehand.
- Sequel Episode: To "Icon".
- Shoot the Shaggy Dog: The team spends the entire episode trying to prevent Tegalus from tipping over into an all-out world war; Daniel eventually manages to broker a ceasefire that would allow Rand to keep their satellite while the Caledonians move to another planet, but the talks break down shortly after the team leave and the two countries end up wiping each other out anyway, making the destruction of the Prometheus and Pendergast's sacrifice completely pointless.
- Some Kind Of Forcefield: The satellite turns out to be protected by one after the Prometheus fires on it, something which Carter hadn't anticipated due to the plans that Kane had given her being incomplete.
- Space Cold War: The situation between Rand and Caledonia, though it pretty much tips over into just plain war by the end of the episode.
- Talking Your Way Out: Daniel negotiates a truce between Rand and Caledonia that allows the team and the surviving crew of the Prometheus to leave the planet unharmed, though this is subverted somewhat by the negotiations failing after their departure.
- Underestimating Badassery: SG-1 and the Prometheus crew underestimate the Ori satellite, both because it was built by a lower-technology civilization and because the incomplete blueprints they had lacked crucial information about its shield and power source. This leads to the destruction of the Prometheus.
- Wham Episode: Earth's first interstellar warship, Prometheus, is destroyed.
- What Did You Expect When You Named It ____?: Lampshaded by the title of the episode itself; in Greek mythology, "Ethon" is the name of the eagle that ate Prometheus's liver as punishment for stealing fire from the gods to give to mankind, making it a rather fitting title for the episode in which his namesake is destroyed by the followers of a Religion of Evil. And all the way back in Unnatural Selection, O'Neill lampshaded the unfortunate nature of the name:Carter: The code name for the project is Prometheus. What's wrong with that?
O'Neill: It's a Greek tragedy. Who wants that? - What Happened to the Mouse?: It's not made clear exactly what happens to Jared Kane, but presumably he's killed in the war that breaks out on Tegalus after the team's departure.
