It's the morning of Steven's birthday, and despite having stayed up the previous night with Garnet, listening to her story about how Ruby and Sapphire met, Steven seems wide awake and full of energy. The Crystal Gems are gathered around the picnic table, all except for Peridot, who is still working on the drill. They ask her if she'd like to take a break and join them. She replies by clicking her welding goggles into place over her eyes and walking off without another word.
Amethyst helps Steven hang his birthday banner over the barn door, since there's no ladder for him to do so, stretching her arms and legs long to do so. He waffles a bit over the banner until she tells him she can't stay stretched out like this all day. He says the banner is fine. She hangs it and returns to her regular size.
Before long, Greg arrives in the Universe van (its door finally repaired), and Connie in the passenger seat. After the two young friends greet each other enthusiastically, Steven says he's so pleased Connie could join them for his birthday. Connie remarks that her parents only permitted it after packing Greg's van with every piece of safety equipment in the state — including a defibrillator.
As they begin to discuss that Steven is 14, Connie is surprised that he's older than she is, since she's taller and he's shorter. Greg shows all of Steven's birthdays from an album:
- Greg: Baby. Toddler. Um, Whaddayacallit ... adolescent? Adolescent. Adolescent. Adolescent. You stagnated for a while there.
Steven seems thoughtful about this. But before he can say or do anything about it, Connie asks Greg to go back to the van so she can show him how to use the defibrillator. They have a quick conversation about Steven, unaware that he's followed them and is eavesdropping from behind the van's doors. They share their "Human Beings" Secret Handshake before returning to the party.
The family shuts Steven in the barn so they can surprise him with his cake. As the barn door closes, the sunlight is closed out, leaving Steven in complete darkness. When they tell him he can come out again, they all gasp in shock as Steven walks out of the barn, now at least six inches taller — his pants come only as far as his mid-shins, and his T-shirt only reaches to just above his belly gem. His voice is even deeper! The present Connie gave him, a pink shirt, won't even close now. He has to wear it unbuttoned to wear it at all.
- Steven: I just had a magical growth spurt! ... Just now.
The family reacts with varying degrees of shock or astonishment, but Garnet reacts with typical encouraging positivity. The party goes on as planned, for the most part. The toy they were playing with gets stuck in a tree, but Steven yanks down a branch so Connie can climb after it. To his dismay, his arm shrinks back to pre-magical-growth-spurt size, but he soon wills it back to match the rest of him. As the day goes on, Garnet and Greg pick out some music, and after some lively dancing, Garnet puts on a slow jam for Steven and Connie to dance. Connie snuggles into Steven's shoulder and closes her eyes. Steven, looking uncharacteristically sweaty, excuses himself to go freshen up. He runs around a corner of the barn and springs back to the size he has been all along.
- Steven: [panting with effort] All I have to do is keep this up for the rest of my life and no one will suspect a thin—
But Greg and Amethyst are behind the barn, play testing his piñata, and are shocked to realize that Steven hasn't really grown — he's been using his shape-shifting powers to stretch himself out and make himself taller, the way Amethyst did when hanging the barn banner. Amethyst warns Steven that it's not healthy or normal to stretch a gem body form like that and that he could really hurt himself that way. But Steven is really very upset at the idea that he's not aging like a human kid.
- Steven: When Connie grows up and becomes President, what's that gonna make me?! First boy?!
Connie and Steven end up sitting together on a blanket, and Connie tells Steven she's really glad they're going to grow up together. Steven gives a stilted look, then vanishes into his clothing! Connie goes searching for him, and he has turned back into a baby! Amethyst regretfully repeats that she warned him about overexerting his shape-shifting, then tries to hand him off to Pearl, who has no interest whatsoever in holding tiny baby Steven. Garnet is willing to take him, and makes faces at him, but he cannot be jollied.
- Garnet: My power means nothing to an infant.
Greg, who raised baby Steven when he was a baby for real, the first time, says he can handle this. A moment later, Greg is at the wheel of the van. Baby Steven is in a car seat, and Connie is in the passenger seat. But baby Steven is still crying uncontrollably. Greg is flummoxed, because when Steven was a baby before, a drive always calmed him down. He offers to take Connie home until they sort through this confusing half-Gem issue, but Connie says she wants to stay. She takes baby Steven's hand and tells him that Greg still has to run his car wash, and she'll watch him then. She'll come visit him when she's done training with Pearl. And she'll spend time with him and be happy to be with him no matter what his size or apparent age is, and they'll have fun no matter what. Baby Steven stops crying. Greg has only a moment to note that with relief before Amethyst, who'd shape-shifted into the car seat, notes that baby Steven needs changing.
The next morning, Connie wakens and the shirt baby Steven was wearing is completely empty! She picks it up and shakes it out, fearing Steven is microscopically small! Connie flies out of the tent in a panic, calling for everyone, but Steven is standing outside, wearing the shirt she gifted him, and he's back to his "usual" size. He sheepishly apologizes to her, saying he wanted to look older for her. She assures him she's okay that he may not age like a human, and as Connie does so, she notices that Steven has a facial hair.
Greg cheerily points out that means he is growing up. Amethyst teases him. But Steven is happy to have a sign that he is aging like a human.
- Adult Fear:
- Greg admits that he doesn't know what will happen as Steven gets older, if he'll stay the same or if he'll age slowly.
- Amethyst gets an Oh, Crap! expression when she realizes that her moment of stretching gave Steven the idea to shapeshift into an older person. She warns Steven that shapeshifting for such a long time has consequences.
- When Steven reverts back to being a baby, the Gems have no idea what to do to change him back. Greg and Connie are barely keeping their cool, although Greg gets to relive raising Steven as a baby.
- Bear Hug: Greg wishes Steven a happy birthday by hugging him and lifting him off his feet.
- Behind the Black: Steven doesn't notice his dad and Amethyst were also hiding behind the barn... when they were standing right in front of him.
- Birthday Episode: It's Steven's 14th birthday.
- Breather Episode: The episode is a break from the Cluster plotline, which is lampshaded by Steven at the beginning when he asks if it's OK to stop working on the drill like this. It still gets relatively serious though.
- Call-Back: After discovering what Steven's doing, Amethyst is quick to point out how forcefully maintaining a larger form than his default one for a longer than average time will have serious repercussions on his body, something she ended up finding out first hand.
- Chekhov's Boomerang: Greg points out to Connie that the Gems didn't raise Steven as a baby; he did, and he remembers what calmed down a fussy infant: long car drives.
- Constellations: Connie and Steven look at the stars and make up constellations. Connie sees one that looks like Dogcopter and she names it "Canis Helicopterus".
- Continuity Nod:
- Connie asks Greg for "Human Beings" advice as he said she could in "We Need To Talk".
- Steven gives Connie a box of the same durian juice they shared in "An Indirect Kiss".
- If you listen carefully when Greg is driving Baby Steven around to calm him down, you can hear the song "Let Me Drive My Van Into Your Heart" is playing.
- Convenient Slow Dance: Garnet and Greg see Steven and Connie dancing so they switch the music to a slow dance.
- Crazy-Prepared: Connie's parents let her stay over at the barn for the weekend after loading up Greg's van with all manner of safety equipment, including a defibrillator.
- Crush Blush: Connie blushes while she's dancing with Steven, admits she's glad he's going to grow up alongside her, and when she assures Steven she's OK if he doesn't grow up normally.
- Does This Remind You of Anything?: When Steven ducks behind the barn to stretch himself again, he notices too late that Amethyst and his dad are also hiding there... and Amethyst is beating Greg's piñata (as in Greg is holding a piñata for Ammy to hit). Also note Amethyst and Greg's formerly close but now weird and estranged relationship.
- Dramatic Drop: Greg drops the pinata he's holding when he sees Steven in normal form.
- Empty Piles of Clothing: Connie freaks out upon finding the shirt Baby Steven was wearing is now empty, fearing he aged back even further into a zygote. Then she pops out of the tent and realizes he has returned to normal and was changing into his new shirt.
- Exact Eavesdropping: Steven hears Greg and Connie talking about the possibility of a MayflyDecember Romance with her and Steven, making him determined to shapeshift into an adult.
- Failed a Spot Check:
- Greg and Steven somehow failed to notice Steven has gone six years—nearly half his life—without physically aging.
- Steven failed to notice that Greg and Amethyst were also hiding behind the barn.
- Foot Popping: Connie pulls a foot up while snuggling up under Stretched!Steven's chin while they're dancing.
- Forgotten Phlebotinum: In "So Many Birthdays", Steven discovered he could change his own age by accident, without any of the usual strain of maintaining a shapeshifted form, and gained enough control over it to turn back to normal. Once Steven discovers he hasn't aged in the last six years, he worries about being a kid forever, even though he should logically have the potential to make himself whatever age he wants indefinitely.
- Fountain of Youth: Steven is temporarily turned into a baby, thanks to a combination of over-using his shape-shifting powers and nerves about appearing too young for Connie.
- Hollywood Gift Wrap: Connie gives Steven his gift in a box with a bow wrapped around it. Steven prepares to pull the bow, but she explains that it's just meant to look wrapped; he can just take the lid right off.
- I Got Bigger: Steven claims to have gotten a "magic growth spurt" when he actually used his powers to look older.
- I Just Want to Be Normal: When Steven realizes he hasn't aged normally in years, he ages up to impress Connie so they can age together.
- I Warned You: When Steven reverts to being a baby, Amethyst says she warned him about shapeshifting for too long.
- Just the Way You Are: When Steven is turned back into a baby, Connie tells him that, no matter what he looks like, she still knows who he is and will be there for him. This helps him get back to normal.
- MayflyDecember Romance: Connie and Greg discuss the possibility that Connie will get older and Steven will remain the same. Steven even brings up the possibility of paedophilia.Steven: When Connie grows up and becomes president, what's that gonna make me? First boy!?
- Meaningful Echo: After the Greg and Amethyst catch him in his normal form, Steven echoes his dad's uncertainty about being half-human.
- Mundane Made Awesome: Garnet tries to stop baby Steven from crying by making faces with her visor off, and expresses her failure in a dramatic fashion:Garnet: My power means nothing to an infant.
- Mundane Utility: Amethyst shapeshifts to get tall enough to raise a banner and turns into a baby seat to hold Baby Steven.
- Not Growing Up Sucks: Steven realizes he hasn't aged in several years. He gets very unhappy at the idea of being stuck as a kid, especially since that means Connie will grow up when he can't.
- Not Helping Your Case: As Amethyst invites Peridot to party, she pops a balloon shaped like Peridot's head.
- Oblivious Guilt Slinging: After Steven fakes a growth spurt, Connie tells him she's happy they can grow up together, making him feel more pressure to Maintain the Lie.
- Oh, Crap!:
- Amethyst and Greg when they see Steven in normal form.
- Connie when Steven turns into a baby.
- Older Than They Look: It turns out Steven is actually much older than he looks but hasn't physically aged since early adolescence. Connie, by comparison, is a little more than a year younger.
- Opt Out: Peridot skips the festivities to continue working on the drill and doesn't speak for the episode.
- Reality Ensues: Connie is surprised that the Gems don't know what to do about Steven-as-a-baby's incessant crying. Greg reminds her (and the audience) that up until recently the Gems had very little experience with humans and even less so with human infants, meaning he raised Steven up to a certain point by himself.
- The Reveal: The episode begins with the revelation that sweet, naïve little Steven is actually 14 years old.
- Screw the War, We're Partying!: The Gems decide to take a day off from building the drill to celebrate Steven's birthday. Steven lampshades this, but Pearl assures him that Peridot, who has elected to skip the festivities, will keep them on schedule.
- Sequel Episode: Similar to "So Many Birthdays", Steven once again faces aging- and shapeshifting-related problems, but this time in the opposite direction.
- Shapeshifter Mode Lock: Steven aged normally up to 8, but has been stuck at that age ever since, and can't permanently change his Shapeshifter Default Form.
- Shapeshifting Excludes Clothing: When Steven reverts to an infant, his clothing doesn't change with him. This is in contrast to how it works for the other gems, whose clothes are made of the same Hard Light as their bodies and shift with them.
- Ship Tease: Steven and Connie wonder how his apparent lack of aging will affect their relationship as they grow up, often sounding like they're particularly thinking of a future love life.
- Shipper on Deck: Greg, Garnet and Pearl try to make Connie and Steven's time together at the party properly romantic.
- Spit Take: Connie learns that Steven is 14 while drinking from a juice box. She doesn't spit out juice, instead she spits the juice box out of her mouth with the straw.
- Status Quo Is God: By the end of the episode, Steven is back to his old height. He has sprouted his first facial hair, though.
- Stylistic Self-Parody: When Steven makes himself look older, Amethyst points out that he finally has a visible neck.
- Sweet and Sour Grapes: Steven pretends to have physically aged so he can grow up with Connie. After Connie tells him she'd still be his friend even if he looked like a baby, he goes back to his usual appearance. Then he finds a facial hair, indicating he is aging at least somewhat.
- This Looks Like a Job for Aquaman: The Gems have no idea what to do when Steven reverts to an infant, so Greg takes over since he nurtured Steven from birth. He takes him for a long car ride in the hopes of getting him to quiet down.
- Unwitting Instigator of Doom: Amethyst stretching herself to hang a party banner gives Steven the idea to do the same with his body.
- Vocal Evolution: Steven gets an older voice after getting bigger, which is achieved by his actor using his natural voice instead of the higher register he usually voices Steven with.
- Voluntary Shapeshifting:
- Despite his track record with this particular ability, Steven decides to age himself up when he realizes that he hasn't physically changed in several years. Though he's gotten better at it, his strains himself by maintaining his altered form for several hours, causing him to revert to an infant when he can no longer hold it.
- Amethyst shapeshifts into a booster seat after Steven reverts into a baby, so that he can ride in the van.