Casey has finally decided to propose to April, and enlists Raph's help in looking for an engagement ring—in the process, a strange old man gives Casey a mysterious ring. Initially delighted, Casey soon comes to regret putting the ring on April's finger when she starts acting strangely and attacking anything that moves.
This episode provides examples of
- Bad Guys Do the Dirty Work: The Purple Dragons' chopper fires at the Turtles' chopper a lot, but they never fire back. Instead, April's One-Winged Angel form takes them out instantly.
- Bad Liar/Oh, Crap!: Apparently, during the time that the turtles were trapped in the future, Hun had told the Purple Dragons that he had personally killed all four of the turtles—but when Hun sees Raph on the streets, he has a hard time explaining to his men how Raph's still alive.
- Battle Trophy: Hun has told the Purple Dragons that the sai and a nunchuck tucked into his belt are this, from when he supposedly killed the Turtles himself.
- Blunt "Yes": Hun's response to when Casey asks if he still wants the ring, despite what it would do to him.
- Bullying a Dragon: While the Purple Dragon goons outnumber Casey initially, once Raph attacks Hun, Casey easily takes most of them out personally.
- The Bus Came Back: Hun is seen for the first time (outside of the opening credits and his appearance in the fabricated tales of "The Journal" last season) since the end of Season 5.
- Catch a Falling Star: Raph catches April and Casey when Casey removes April's ring, reverting her back to her normal human form a hundred feet up in the air.
- Clingy MacGuffin: During a moment of clarity, April tries to take the ring off, but it's stuck.
- Clothes Make the Maniac: The Ring of Yin.
- Evil Makes You Monstrous/ Power-Upgrading Deformation: April's demon form. Thankfully it doesn't last.
- Fake Ultimate Hero: Hun tried to build up his rep by claiming to have personally killed the Turtles and getting some replica weapons as proof.
- He Cleans Up Nicely: Casey looks particularly swoon-worthy in his tux.
- Hope Spot: When the demonic April attacks the Purple Dragons' helicopter, Mikey wonders if this means she's still on their side. Her turning her attention to the Turtles' helicopter quickly sets him straight.
- Irony:
- When April starts behaving strangely, Casey worries it means she's going to change her mind about getting married, but Raphael is certain there's a logical explanation for all this. Cue a demonic April bursting through the wall.
- Out searching for the ring, Hun is most amused that his "old friend" Casey Jones has led him right to it.
- Letting Her Hair Down: Inversion: If April's hair isn't in her trademark bun, the situation generally isn't good. When she turns into a demon it falls loose completely, yet inexplicably returns to its trademark bun when she becomes human again.
- My God, What Have I Done?: Casey over the ring he gave April causing her to go demonic.
- One-Winged Angel: April's demon form may apply.
- O.O.C. Is Serious Business:
- April can immediately tell something is up when Casey wears a tuxedo.
- The ring causes April's anger to surge out of control.
- Power Glows: The Ring of Yin.
- Properly Paranoid: As Hun points out, the Shredder potentially returning would be a significant threat to his well-being given his defection and reforming the Purple Dragons into a credible rival to the Foot, and that's why he's scrambling to prepare for it.
- Race Against the Clock: Hun is in a rush to gain a powerful weapon because of rumblings that the Foot is reforming and the Shredder will soon return.
- Real Men Wear Pink: Mikey asks if he can be April's Maid of Honor. At first this just seems like Mikey's signature humor, but in "Wedding Bells and Bytes" (the series finale) its revealed that he actually is her Maid of Honor
- Red Eyes, Take Warning: April when under the ring's influence.
- Tantrum Throwing: At first it seems like April is doing this, throwing dishes at Casey because he put them away wet, but it was actually due to the Ring of Yin's influence.
- Temporarily a Villain: April, thanks to the Ring of Yin.
- That Came Out Wrong: Casey's marriage proposal to April:Casey: April, I love you like... like Gretzky loves hockey, and I
wanna play you for the rest of my life...- Dah! I mean your life! I-I mean Gretzky's life! - I mean- - Voice of the Legion: April when she's wearing the Ring of Yin.
- Wacky Marriage Proposal: Casey tries to make the proposal all romantic and memorable by wearing a tux and doing it out on a lake, but he's extremely nervous and bugs start to swarm. After they both get drenched, Casey just cuts to the chase with a far more simple proposal.
- Wham Episode: While the overall story of the show hasn't changed, the episode does feature Casey and April getting engaged after dating the entirety of the show's lifespan.
- With This Ring: I will turn you [April] into a demon.
