Leonardo, tired of Raphael's constant criticism, lets his brother try his hand at leadership for a while; Leonardo meets Karai, a beautiful and dangerous female ninja who tries to lure him to the dark side.
This episode provides examples of:
- Armor-Piercing Slap: April does this to Leo when he tells her that girl he's hanging out with is in the Foot Clan.
- Borrowed Catch Phrase: Raph yells Mikey's "Booyakasha!" when he delivers the final blow to Snakeweed.
- Call Back: Snakeweed is back from "Rise of the Turtles".
- The Complainer Is Always Wrong: Raph. Who else?
- Dark Action Girl: Karai. She is a "beautiful and dangerous female ninja", of course.
- Enemy Rising Behind: Snakeweed behind Raphael as Leonardo tries to explain why he's with Karai.
- Foreshadowing: Once again, Space Heroes. Particularly in the case for "Enemy of My Enemy", where Leonardo and his brothers betray Karai first.
- Green-Skinned Space Babe: Captain Ryan gets a Blue-Skinned Space Babe in this episode. It doesn't last.
- Hammerspace: That comic book April hits Leo with comes out of nowhere.
- Heroic BSOD: When Michelangelo gets hurt during Raphael's stint as leader, he can't figure out what to do and Donatello has to tell him that they need to retreat.
- Literally Shattered Lives: Snakeweed gets frozen and then shattered to pieces. It doesn't last.
- Never Trust a Trailer: The official promo of this episode only shows the conflict between Leo and Raph. Karai and Snakeweed aren't even mentioned.
- Same goes for the summary. Karai doesn't "lure [Leo] to the dark side", she just tries to push his buttons a little.
- Not So Different: Leo and Karai get into this with each other.
- Sibling Rivalry: Leo vs Raph.
- We Can Rule Together: Karai trying to convince Leo that he's not as good as he pretends to be. Also inverted with Leo trying to convince Karai that she's not as bad as she pretends to be.
- What the Hell, Hero?: Splinter calls out Leo for handling his leadership over to Raph. Later, he calls out Raph on the consequence of being leader thanks to Mikey's injuries.
- April also didn't approve of Leo being interested in his enemy, which leads to her telling the others.