On the planet Mon Cala, tensions are rising between its two sentient species, the Mon Calamari and the Quarren, exacerbated by the recent murder of Mon Calamari king Yos Kolina, leaving his young son Lee-Char to take the throne. However, the Quarren are reluctant to accept him as monarch, believing him to be too young and inexperienced to lead. Senator Padmé Amidala and Jedi Knight Anakin Skywalker arrive to represent the Galactic Republic in the hopes that peace can be maintained. However, the meeting goes poorly, as Separatist ambassador Riff Tamson, there at the request of the Quarren, inflames tensions, persuading them to swim out on any peace deal. Realizing that a civil war is inevitable, Anakin, Padmé and Captain Ackbar of the Mon Calamari guard call Master Yoda for reinforcements. As a force of clones led by Jedi Master Kit Fisto and Anakin's padawan Ahsoka arrive to assist the Mon Calamari, the Separatists also deploy reinforcements as the fight for Mon Cala begins.
- Alliterative Title: "Water War".
- Almost Out of Oxygen: Anakin gets jumped by a Quarren soldier who pulls his helmet off before Anakin kills him, and nearly drowns trying to get it back while fighting before Ahsoka returns it.
- "Ass" in Ambassador: Riff Tamson, representing the Confederacy of Independent Systems, is incredibly rude and demeaning to everyone else, especially Lee-Char. It's pretty clear he's there specifically to stir up conflict between Mon Cala's two peoples.
- Blatant Lies: When Ahsoka returns Anakin's helmet after he nearly drowned attempting to get it back, he says he had the situation completely under control. Her response is simply that she knew he was going to say something like that.
- Bloodless Carnage: There's a lot of people getting stabbed with bayonets and Riff Tamson swimming around biting people to death, but no blood at all.
- Call-Back: Separatist aqua-droids return from "ARC Troopers".
- Call-Forward: The head of the Mon Calamari guard is one Gial Ackbar. He even says "It's an attack!" in a nod to his famously memetic line "It's a trap!"
- The Cameo: Captain Rex has a brief appearance onboard the Jedi Cruiser that brought Kit, Ahsoka, and the scuba troopers to Mon Cala, telling Kit that everyone's ready for deployment.note
- A Child Shall Lead Them: Teenager Lee-Char is next in line for the throne of Mon Cala, but he's uncertain of whether he can be an effective ruler, something Riff Tamson preys upon during the council meeting. Lee-Char himself admits that he's not trained to lead an army.
- Dare to Be Badass:Ackbar: Hear that? They're cheering for you.
Lee-Char: They're cheering for them.
Ackbar: [hands the prince a rifle] Then make it for you. Come on! Lead!
- Electric Jellyfish: The hydroid medusas are a cyborg example, "half machine, half monster".
- Foreshadowing: It's made clear that Riff Tamson was sent to the Mon Calamari system to provoke conflict.
- Guns Akimbo: Captain Ackbar, at one point during the battle, is seen wielding two rifles.
- Honour Before Reason: Mon Calamari traditions demand that the inexperienced Lee-Char command the troops, even though he knows very little about what he's doing, something Anakin points out to him and Ackbar. Lee-Char also refuses to retreat to a safer position when Anakin insists he do so, since his place is with the soldiers.
- Immune to Bullets: The hydroid medusas are unaffected by blaster fire.
- In the Back: In the opening montage, Yos Kolina's corpse is seen floating in the throne room with a dagger in his back.
- Know When to Fold 'Em: During the second attack on the capital, Lee-Char is reluctant to retreat since he needs to be brave, but Ackbar has some advice for him:"There is a time to attack, and a time to retreat. And now is not the time to be brave."
- Pet the Dog: Despite being on opposing sides, Nossor Ri does offer his condolences to Lee-Char over his father's death.Nossor Ri: Your father was my trusted friend. I am sorry for your loss.
- Tempting Fate: Lee-Char gives a speech where he says he doesn't believe the Quarren will attack. Naturally, the Separatist assault on the Mon Calamari capital begins moments later.
- Unwitting Pawn: Count Dooku told Tamson that Nossor Ri would be willing to deliver the planet into Separatist hands, and Ri doesn't know that the Separatists' plans involve leaving Tamson in control of the planet afterwards.