In her first appearance, Nova is sent from the future to destroy the newly built Slug Gigant MK II, which she succeeds in doing.
Nova attacks a Regular Army base with assistance from a new Kraken. Nova's almost succeeds in taking the base, but Mello arrives and helps fight off the attack. Exchanging a few words with Mello, Nova retreats to prevent from being captured.
Nova later returned with a special Kraken to assist the present day Rebel Army. During an attack by the Ptolemaic Army, Nova fights Lucy but is forced to retreat when Lucy's frog mecha intervenes.
Cleopatra's Pleasure Tour
As the Rebel Army were conducting an experiment in the desert, powering up a Big Gate, Nova arrived from the futures through and, because her mission was interrupted, re-prioritizes her objectives and runs off to a nearby town where she begins causing havoc. El Dorado then arrives and asks Nova for her business, informing her that he's come to investigate a strange energy source. Nova refuses to listen to reason and battles the adventurer.
As Nova prepares to take her power limits off, Vita arrives and Nova turns her attention to her. Nova introduces herself to Vita, who in turn introduces herself to her. Nova stays with the Rebels and at night Vita comments on Nova's strength. Nova states that she resented the human Vita and wanted to destroy her if she could go to the past, but does not, as Vita is a cyborg now. Nova admits that she's jealous of how Vita has friends and family she wants to protect and gives Vita the Union as a gift before she is called back to her time.
When Cleopatra and her servants arrive at town and approach the Big Gate, Nova appears to attack her as the Union separates and fights alongside Nova. With little time left, Nova attacks and surprises Cleopatra is with her durability. Before the battle can continue though, Nova and the Union are recalled to the future.
A Christmas Miracle
Nova talks about how she learned that humans are born from mothers and that they are weak when born, so they are protected until they develop into adults. She explains that she gained consciousness three days after being created, before finding someone that looked similar to her. She recalls three memories; to eradicate the enemy, have no sense of pain, and to dedicate oneself to the Rebel Army. The base Nova was at is then attacked by an unknown enemy and Nova and the other units are forced to go into battle. The battle leaves Nova as the only one that survived.
While repeating her directives to herself, Nova is found by Midori after she notices the fragment she has with her. Nova tells her that she'll give her fragment to her. Midori asks Nova if she has someone to be with, but Nova states she's always alone, thus she has no one to give gifts to and doesn't want that responsibility. After Midori catches the fragmen,t she wishes Nova a Merry Christmas and a light engulfs Nova, causing her to fall unconscious as Midori looks on with a sad smile. Nova then recalls her memories from Vita and realizes what they meant, that she is Vita's only hope. Nova is later seen praying for Midori to be happy.
Everlasting Summer Returns
When the Rebel army is playing volleyball at a beach in the neutral zone, Nova acted as a cheerleader for them as they played against the Regular Army's Rita, believing it was a mission. Suddenly a mysterious shockwave ripples across the island and causes everyone to start fighting each other, perplexing Nova as the island is a no-combat zone.
After Odette, crash-landing her ship in the process. Odette came as she knows summer is one of the more popular human activities and is glad she arrived on time, but notices that something is off. Rita attacks several Rebel soldiers but Nova intervenes to protect them. She researches Rita and states that she is a country gal, angering her and causing her to attack Nova. After Nova defeats Rita and ponders what could be causing people to become violent, the Invader Odette appears, having recently arrived on the island and informs them that someone has set loose a large quantity of "Boreal Matter", a substance used on Mars as a behavioral stimulant that affects organisms reliant on oyxgen and hydrogen. Rita then sights Rumi and Fio arguing in the distance and runs off to stop them, while Nova and Odette go find the culprit behind the Boreal Matter unleashed on the island.
Nova soon finds a Mars Brain Robot and deduces that the Professor is behind the Boreal Matter being spread across the island. Meanwhile, Odette gets into an altercation with Miharu after her appearance causes Miharu's soldiers to become infatuated with her and to leave Miharu. After defeating Miharu and learning about a Mars Brain Robot she saw, Odette and Nova eventually reach the source of the boreal matter and confront the Professor. The Professor reveals that, because of all the prominent fighters on the island (Rita, Eri and Miharu), he plans to collect their data to create the ultimate combat lifeform. While Marty uses the Rugname X to attack Odette, Nova battles the Professor. Nova demands the Professor to return everyone to normal, but the Professor tells that he already has what he wanted and that the Boreal Matter's effects are only temporary and will dissipate soon. Odette then takes Nova away before the Rugname can crush them and they return to the beach.