You are Ember Edwards, the least popular girl in school, but everything changes when you find a doorway to another world.
Ember Edwards is the most unpopular girl in school. Her parents are irresponsible slobs who rarely care about her, and she is constantly bullied at school.
Things seem to get better for Ember when she is asked out by two boys to the prom. On the day of the dance, the most popular girl, however, Alice, reveals that it was all a trick - the boys had to embarrass themselves by dating Ember to get a kiss from her. Devastated, Ember runs off. She enters an abandoned room labelled "universe splitter" with two doors inside. After she gets trapped inside and flashes of light frighten her, she opens one of the doors, which sucked her into a new world, Eterna.
Upon regaining consciousness, Ember meets a man named Kellan Keystone, a member of the Divine Council. Kellan informs her she is the most feared being in Eterna and he is ordered by Lady Astaria to kill her. He warms up to Ember and lets her live at his apartment. After a visit from Kellan's colleague Ashton "Ash" Cross, Ember's takes a nap while Kellan cooks. Other members of the Divine Council break in, interrogate Ember and arrest Kellan. Kellan cryptically orders her to "Give the Purepopper to Noface".
Ember explores the town, socialising with the townspeople and cracking the code: Purepopper is the name of a fizzy drink, which was discontinued after holy fountain nicknamed "Noface" was defaced. Kellan is telling her to deface the fountain so she could sneak onto the van and travel to the prison. Ember finds a Purepopper in the fridge but runs into Ash, who also warms up to her. Together, they vandalise the fountain, sneak onto the van and travel to the prison. They get caught, but Grand Consul Raven Rathbone let Ember, Ash and Kellan go.
After a talk, Ember retires to Kellan's bed, Kellan sleeping on the couch. The next day, he takes Ember out shopping for clothes. He, Ember and Ash go to the cave system to find a way back to Earth. The trio go to the library, where they scare the librarian and read the Book Of Origins, which shows that Ember can't escape back to Earth.
Ember goes for a picnic with Ash, who shares a story about how he made a love letter for himself, waiting for a girl to give it to. Kellan deduces Ember had a picnic with Ash, scolds her and declares "I own you". Ember, shocked and scared, flees the apartment, where Raven, upon learning Ember can't get back to Earth, arrests her and brings her to Lady Astaria.
Ember learns that Lady Astaria is actually her older alter ego who was split from her when she entered the universe splitter room. While the Player Ember entered the first door, Eterna in the present day, her other half went through the second door to Eterna fifty years earlier. She is the angry, rebellious side of Ember while the Player's version is the weaker, more forgiving one. Astaria has Ember poisoned but manages to redeem her with a quote from her teacher "Anger is an acid that can do more harm than good to the vessel in which it is stored than anything it is poured". Ember survives the poisoning and Astaria and Raven flee.
Kellan and Ash continue to take care of Ember as the Consuls, Astaria's bitter ex-employees, pursue her. Kellan tortures a consul to death, much to Ember's horror. Kellan tells Ember he was taking out his fantasy of revenge on the man who killed his parents. The two stay over at Ash's home, and Kellan is silently furious when he sees Ember and Ash kiss. While Ash and Ember went out to buy groceries, Ash's parents are killed by Consuls. Ember retrieves a video tape and learns that Kellan killed Ash's parents.
Ember and Ash try to escape Kellan's clutches, and end up in Earth again through the universe splitter door. The two have a dance at the prom, much to Alice's shock. However, Kellan returns and lures the duo to school, posing as Ember's principal. The two subdue Kellan, but Ash breaks free and Ember corners Kellan in the basement. Kellan paralyses Ember and starts stabbing her, but luckily, Astaria appears and tackles Kellan. Ember and Astaria are both found and determined to be identical people with different ages, which the press finds to be due to the universe splitter room and dubs "The Ember Effect." But they cannot exist together in one universe, and Lady Astaria soon fades away.
Kellan, who followed Ash and Ember into Earth, continues to pursue Ember and tries to kill her multiple times. He sends Ash back to Eterna, and Ember must try to reach him while people on Earth demand to dismantle the Eterna machinery, threatening the existence of the entire world. After finding the machinery in a government building, Ember runs into Kellan and shoots him. Without Kellan in the way, Ember tries to enter the right world but fails on her own. She ends up in the world of Phoenix Faraday, from The Phoenix Prophecy. Phoenix points her to the wavecrusher machine, which takes her back to Eterna, and she saves Ash from being stuck between worlds.
In Eterna, Ember and Ash resume their relationship and decide to get married, not knowing how long Eterna will last in the hands of Earth's people but wanting to make the most of their time together. Back on Earth, it is revealed that a government employee ordered to dismantle Eterna decided to keep a piece of it intact. This piece happens to be a glowing green cube which he suspects is the key to Eterna's continued existence. Little does he know that, as he wishes Ember a happy ending in Eterna, it is already truly happening for her.
Ember Edwards - The main protagonist in the story, a young girl accustomed to being rejected by everyone around her. She stumbles upon a universe splitter room which takes her to Eterna.
Ashton Cross - A boy who helps Ember through Eterna. He becomes her boyfriend and later husband.
Kellan Keystone - Another boy who helps Ember in Eterna. He is initially kind to Ember, but turns out to be a psychopath. In the latter part of the story he tries to kill Ember multiple times.
Lady Astaria - Ember's alter ego, her angrier self who went through the second door to Eterna and is fifty years older than her.
Ember's Parents (Karl and Linda Edwards)- Ember's abusive parents.
Alice - The most popular girl in school, who plays a cruel trick on Ember for prom.
Ivy - Alice's friend, who participates in the prank on Ember. She lends money to Ember, and .
James - Kellan's concierge. He is unaware of his boss's villainy.
Grand Consul Raven - Lady Astaria's right-hand man, who spares Ember because he was in love with Astaria when he first met her, and Ember is the exact copy of her younger self.
Ashton's Parents - Two very loving adults in which the mom immediately offers to be the motherly figure Ember's never had after discovering from her son the horrible home life she has had. However, they are later killed by Kellan.
Phoenix Faraday - From The Phoenix Prophecy, a girl who helps Ember return to Eterna and find Ash again.