After learning the truth about his mother's real identity, Steven feels lost, but with the discovery of a new power and the Diamonds coming to Earth one last time to fulfill their revenge, he will have no other choice but to fight to protect his home, family and friends. Will Steven be able to end what his mother started?
One Last Song provides examples of:
- Ain't Too Proud to Beg: After Lars refuses to shatter Emerald after beating her at her own game, she then resorts begging him to do it because she is more afraid of what the Diamonds would do to her for her failure.
- Doing Research: Ever since the trial brought up that Rose Quartz might not have shattered Pink Diamond, Blue Diamond and the Zircon that brought it to light have since been digging into classified information on the event with the intent of finding an answer.
- Expecting Someone Taller: When Emerald captures the Off-Colors, Lars jokingly invokes this, especially funny considering that Emerald is actually the tallest one there in-person.
- I Want Them Alive: Yellow Diamond ordered (much to Emerald's reluctance) to bring in the Off-Colors alive, wanting the pleasure of shattering Rose Quartz. It is not until Lars manages to convince her to kill him right away is he able to outwit her.
- Nice Job Breaking It, Hero!: Steven's de-corrupting process seemed to start working (with Ruby and Sapphire baring witness) only for Pearl and Amethyst to show up and "save" them from the corrupted gem.
- Some time after, Steven wants the first gem he curse of corruption to be Jasper, feeling like she deserves to know the truth after all of the trouble his mother (both as Rose Quartz and as Pink Diamond) put her through. Naturally, the first thing she does is poof him after easily demolishing the cage Peridot made for her.
- Start X to Stop X: Having discovered that Steven himself has the gem of a diamond, he figures that he alone has the ability to undo the Corruptive "song" of the other diamonds. How does he do it? He sings of course.Peridot: Oh yes! That is really remarkable Steven, being able to repair damage made from the Diamonds themselves! Although with you being a Diamond it shouldn't have been such a surprise.
- Two Lines, No Waiting: Lars and the off-Colors leaving Homeworld did not go unnoticed, Yellow Diamond being the one who sent Emerald personally to capture them, presuming that Rose (Steven) was on the same ship.
- Villain Respect: Blue Diamond defends Blue Zircon and stands up to Yellow Diamond when she wants her shattered, pointing out that she was a part of her court and is thus beyond Yellow Diamond's wrath, even acknowledging that she was brave to openly challenge their preconceived assumptions to bring the truth to light.
- What's Up, King Dude?: When Peridot (having just found out that Steven is actually a Diamond) sees Steven, she reflexively gives him a diamond salute, only for him to talk her down, convincing her that he does not want their friendship to change in-spite of the circumstances.
- Worthy Opponent: After Lars and the off-Colors turn the tables and leave Emerald at their mercy, she concedes that he is the better captain.