"History of All Gems" is a really corny episode of All Dogs Go To Heaven: Watch Steven Universe Instead.
David is helping Lapis Lazuli and Peridot do repairs on the barn on the way home. He has a report to work on, and he reveals that he has to write a topic on Gems (which intimidates him because he's a guy), much to Lapis and Peridot's offense.
STORY ONE: Lapis Lazuli tells David of how Gems gave man fire with a simple game of fetch, which was by a caveman throwing a stick just to get rid of a very annoying Peridot, only for the Peridot to use a burning stick against a T-Rex in order to prove herself useful, so the caveman accepts her. David tells Lapis his teacher won't accept that.
STORY TWO: Peridot tells David a more believable story: one in which a young architect of Ancient Egypt shows some ideas, among which are an igloo and the Eiffel Tower, much to the Pharaoh's dismay. So much of it, that they have the architect taken away, but upon seeing a Pearl building Pyramids to please her Diamond, he pulls away and reveals it.
Before David could give Peridot any feedback, he falls asleep, much to Lapis Lazuli's worry over a possibility that David will flunk, become jobless, and live under a bridge with Ronaldo Fryman.
Lapis decides to help David with his report by her and Peridot doing a story on his behalf (David's way). She then tells Peridot to start typing as Lapis tells the story. Because Peridot doesn't know how to spell "Gems," Lapis decides to type by herself. Peridot comes up with an airplane as an idea, giving Lapis the idea of how Gems changed the course of history.
STORY THREE: During battles in Europe, two dogs (portrayed by Peridot and Lapis) are working with a human army whose general reveals the foe is working on a secret weapon in a factory and orders them to blast it to smithereens by night, passing foggy mountains and fire cannons. Because the human soldiers get sick because of someone unintentionally washing his socks in a teapot, Peridot and Lapis thank their lucky stars they don't drink tea. After revealing this mission could change the course of history, the general gets sick, too, and leaves. Lapis decides to take the job by air, much to Peridot's dismay as "flying is dangerous," but Lapis says it is crashing that's dangerous.
STORY THREE (continued): Lapis paints a picture of Steven Universe on the plane, calling it the Universe. In the plane, Lapis has Peridot check for fuel, flaps, the tail, and meepmorps (double check). Lapis then flies the Universe, and Peridot, dressed as an engineer, makes adjustments to the engine. Lapis tells Peridot to sit down, so she does. Upon Peridot revealing that she didn't know Gems could fly so well, Lapis manifests her water wings.
While Lapis reveals that the Gems were flying into Diamond territory, Peridot makes plane noises, pretending to be a plane, waiting for a turn to type out of desire for being a pilot. Lapis agrees, only on the condition that Peridot remember that "Gem" does not have a J in it. (Unless you're Jerrica Benton.) Peridot starts typing and continues the story...
STORY THREE (continued): ... revealing that Lt. Peridot acted so well that she fused with the plane (meaning she made the plane act like a cat). They creep into Homeworld, as the Ruby Squad shoots the Universe, much to Lapis Lazuli's too-late warning. Among the ammo was, "as always," the kitchen sink, sending the plane down to the mountains.
STORY THREE (continued): While the plane is diving, Lapis screams...
... while Peridot is just typing Rs on the screen in his sleep. Lapis wakes her up. Peridot is shocked to see what he had done.
STORY THREE (continued): ... the plane crash-lands on the snow on a cliff above the Diamond territory.
Itchy then says she is tired, to Lapis Lazuli's sarcastic thanks for writing her into a corner. Lapis then grabs Peridot and tosses her onto David's bed to continue the story.
STORY THREE (continued): Because Lt. Peridot is unconscious, Major Lazuli vows to finish the mission. Deciding to find an engine for the Universe, she checks out the Homeworld airfield where her skills will be put to the test. She slides down the mountain into the water and checks a crate, one of the planes, a Gemhole, and the inside of a building.
Major Lazuli then brings out an engine with a rope and repairs the plane, proving that Gems can repair planes, though few ever get the chance to prove it.
Then the Gems move the Universe, but instead of acting as such, it moves on land at first, but it changes. It flies again. It passes Heaven, making angels move out, and Rose Quartz angrily points at the plane, yet Major Lazuli salutes to her.
Yellow Diamond, to her dismay, reveals a Lapis Lazuli is changing the course of history. She is the head of the enemy, so she calls out her best quartz warrior, Jasper. Major Lazuli tries to escape on her water wings, but it doesn't work. Jasper shoots the Universe down, but Major Lazuli does a trick to make Jasper and her fellow pilots crash into each other and use parachutes as Lazuli calls that "plane dead." Jasper tells the base to send out the secret weapon: the Cluster.
In "reality," Lapis wakes Peridot up and needs her to help type. She is shown to have missed 7 pages.
STORY THREE (continued): Lt. Peridot is conscious again, so Major Lazuli has her man the bomb site. As they are moving out into position, the Cluster comes out. It nearly explodes, which would have destroyed the planet. Major Lazuli then commands Lt. Peridot to immediately drop their bombs on the Cluster and it falls on the factory, much to Jasper's dismay.
Finally, the story is finished, and a tired Peridot says, "The end." It is already morning, and David wakes up to see them still here, but he is shocked to forget about his report. Lapis and Peridot reveal what they did. While appreciating what they were trying to do, David tells them his teacher wants him to write his own report, though Peridot points out he ran out of time. David then says it is Saturday morning, meaning he had time to do his own report alone. Though grateful to have help from them, he says he cannot use that report; however, he accepts the fact that Gems are man's best friend.
- This is David's final appearance overall.
- David sounds slightly older in this episode than anywhere else. This is because his voice actor, Adam Wylie, was going through adolescence.
- This is unknown why, but David's stepmother is blonde with curly hair here, though she was brunette with wavy hair in All Dogs Go to Heaven 2.
- In this episode, according to the story Lapis Lazuli and Peridot invent, Steven Universe is the namesake of an airplane, known as the Universe, though Rose Quartz (of whom Steven is a reincarnation) makes a cameo, looking angry (though not enough to even be furious) at the sight of the plane.