Discovering that Caleb's father is alive and imprisoned in the Underwater Mines, the heroes go to rescue him, while the villains prepare to ambush them.
- Always a Bigger Fish: Mentioned by Jade when the heroes see a big squid-crab creature that's followed by an even larger creature.
- Commonality Connection: Jade and Caleb bond over their similar headstrong attitudes and senses of loyalty.
- Crazy-Prepared: Alchemy brought along several of the Talismans, as well as some walkie-talkies. Tohru also developed an onion-based anti-Oni chi spell in case Tarakudo attacked.
- Even Evil Has Standards:
- Since all Aketon did was make weapons for the Rebellion, Phobos' only punishment was that he had to fix all the tools in the underwater mines.
- When Caleb learns that Shendu was planning to kill around four billion people, he expresses the belief that as much as he hates Phobos with a passion, not even he would seriously contemplate genocide.
- Genre Savvy: When the heroes are hashing out a plan to save Caleb's dad, Jade notes how in every movie she's seen, mines have a nasty habit of collapsing. True to form, the underwater mines end up collapsing due to Tarakudo's actions during the fighting.
- So Much for Stealth: The heroes split up, with one of the groups distracting Phobos' forces on the surface while the others look for Julian in the mines. Once Tarakudo shows up, they stop being stealthy.
