The group travels Spira on their airship, the Celsius. The group is led by Brother, the pilot, his right-hand-man Buddy working as the navigator. They are assisted by the "whiz kid" Shinra whose technical innovations help support the field operatives, Yuna, Rikku and Paine, or "YRP" for short. Shinra has developed technology that lets the Gullwings use the spheres they salvage as dresspheres, using the knowledge and memories stored within the sphere to enhance the girls' battle capabilities.
The Gullwings were originally an 'all-Al Bhed' group founded by Rikku, Brother, and his old friend Buddy. They were shortly joined by Shinra, Paine, and lastly Yuna. Two years have passed since Yuna defeated Sin. Back on Besaid Island, her quiet life was shattered when she received a message from Rikku, who had a gift from Kimahri—a sphere he had found on Mt. Gagazet showing a man with a striking likeness to Tidus, her lost love.
During her time with the Gullwings, Rikku serves as a role model for Yuna, as she mimics some of Rikku's eccentric behaviors and uses some of her expressions, though others sometimes reprehend her for this. Yuna has also gotten in touch with her Al Bhed heritage by learning the language. Though Yuna's friends tease her for always getting dragged into trouble and being a pushover as she's unable to refuse a call for help, she can be stern and intimidating if angered. Yuna has developed a distaste for sacrifice in the name of victory and peace, a trait Tidus instilled in her. Some changes in her personality have her resembling Tidus, including her looks, attitude, and combat style in certain dresspheres.
With their airship, the Celsius, Yuna, Rikku, and Paine travel Spira in search of treasure spheres. They gained a rivalry with the Leblanc Syndicate and its leader, Leblanc, stole Yuna's Garment Grid to perform a concert in her likeness. Rikku and Paine crash the concert in Luca while Yuna dons a moogle costume as disguise and keeps a low profile. When Rikku and Paine chase Leblanc and her two henchmen, Logos and Ormi, out to the docks, Yuna joins the battle and reclaims her Garment Grid. Afterward, Yuna finds herself dancing uncontrollably being overcome by someone else's excitement.
The Gullwings explore the recently discovered Floating Ruins at the peak of Mt. Gagazet and run into Leblanc, Logos, and Ormi again, racing them to the top. Leblanc and her goons get stuck and the girls claim the treasure sphere that contains images of the ancient Zanarkand.
News spread about an "awesome sphere" discovered in Kilika drawing the attention of both the Youth League and New Yevon. Yuna believes if the two factions cannot decide who should have the sphere, the Gullwings should take it. They seize the sphere whose footage shows the mysterious man standing before a large weapon, mentioning someone named Lenne. Yuna doubts the man is Tidus and wonders who Lenne is.
Having seen the sphere, Yuna decides to return it. During her mini-concert on the deck of the Celsius that night, she gets angry and storms off to bed. The next morning Yuna dreams of her and Tidus being gunned down by soldiers in front of the machina weapon shown in the sphere, though Rikku tells Yuna to "blame it on her new jammies" since she was sleeping while wearing the Songstress dressphere.
The awesome sphere is returned to either the Youth League or New Yevon, and it is learned from Nooj or Baralai the colossal weapon is called Vegnagun. Leblanc, Logos, and Ormi broke into the airship while they were away and stole the broken sphere they obtained from the Zanarkand Ruins. Yuna, Rikku, and Paine steal uniforms from members of Leblanc's gang to sneak into Chateau Leblanc in Guadosalam where they discover Leblanc already had the other half of the broken sphere and stole theirs to make it whole. Leblanc, Logos, and Ormi fight them, but afterward, Leblanc lets the girls watch the restored sphere.
From the sphere, it is learned Vegnagun hides underneath Bevelle. Forming a truce with their rivals, the sphere hunters enter the underground passage in the Bevelle Temple formed after the fayth's disappearance brought about by Yu Yevon's defeat. In a secret complex filled with machina, the YRP reaches Vegnagun's lair and faces an antagonistic Bahamut. Yuna begs it to stop, but the girls are forced to fight it. The sphere hunters find Vegnagun is gone and a large hole is left in its place.
Fiends pour out of the temples, and the leaders of the Spiran leading factions—Nooj, Baralai, and Gippal—go missing. Following the battles with aeons in their respective temples, deep holes are left behind in the Chambers of the Fayth where Shinra says the fiends are coming from. After defeating Ixion in Djose Temple its surprise death blow attack sends Yuna falling into the chamber's hole and she lands in the Farplane. She finds herself wearing the Songstress dressphere that emits pyreflies and she encounters the mysterious man from the spheres who reveals himself to be an unsent named Shuyin.
Calling her Lenne, Shuyin tells Yuna he despises Spira's inability to change after a thousand years as everyone continues to fight. He plans to use Vegnagun to destroy Spira to end all wars and avenge Lenne's death. As Shuyin embraces Yuna she feels emotions that aren't hers and wonders if they belong to Lenne.
Shuyin's spirit has possessed Baralai to travel to the heart of the Farplane, and Nooj and Gippal have been following their friend to save him. Nooj and Gippal give Yuna spheres for Paine and follow Baralai deeper into the Farplane. Frustrated with getting more questions than answers, Yuna tries to escape the Farplane. Close to giving up, she hears a familiar whistle and sees an image of Tidus and follows him to emerge in the Bevelle Underground.
Back on the Celsius Yuna tells everyone what happened. Throughout Spira, tension rises between the Youth League and New Yevon with their leaders missing, so Yuna performs a concert on the Thunder Plains to express Shuyin's hatred of war and unite everyone. During the concert, Lenne's spirit appears from the Songstress dressphere. It is revealed Shuyin and Lenne were gunned down by Bevelle soldiers after she stopped him from activating Vegnagun a thousand years ago.
Lenne was a famous songstress and summoner from the ancient Zanarkand who was called to the front lines during the Machina War, and Shuyin had tried to use Vegnagun to save her. When she died her memories coalesced into a sphere, which the Gullwings now use as the Songstress dressphere. Now knowing Lenne chose her to help Shuyin's spirit rest in peace, Yuna plans to try talking to him and tell him how Lenne felt.
Using one of the holes in the temples, YRP descends into the Farplane in search of Shuyin and Vegnagun. Bahamut's fayth appears to Yuna and explains the aeons were corrupted by Shuyin's despair, and thus had fought her. When Yuna learns of Nooj's plan to draw Shuyin to try and possess him and then take his own life, she objects, wishing not to repeat the actions taken to defeat Sin, her plan to convince Shuyin to yield for Lenne's sake. After destroying Vegnagun and besting Shuyin, Lenne's spirit puts Shuyin's hatred to rest and they fade away together.
Bahamut's fayth asks if Yuna wants to reunite with Tidus. If she accepts, Tidus will surface off the Besaid coast and a joyous reunion is celebrated.
In Final Fantasy X-2, Rikku continues to care about Yuna's welfare while encouraging her to have more fun in life. She has become Yuna's role model who copies her erratic behavior and unique expressions, though Rikku sometimes reprimands Yuna for using foul language. Rikku remains the ever upbeat and somewhat reckless individual, occasionally causing trouble for her friends.
The Gullwings gain a rivalry with the Leblanc Syndicate, another sphere hunting group led by Leblanc. One day, Leblanc steals Yuna's Garment Grid and performs a concert in Luca while posing as Yuna. Rikku and Paine crash the concert while Yuna dons a moogle costume to keep a low profile. Rikku and Paine chase Leblanc out to the docks and Yuna joins the fray and reclaims her Garment Grid.
The Gullwings explore the recently discovered Floating Ruins at the peak of Mt. Gagazet and claim the treasure sphere that contains images of Zanarkand. At the Zanarkand Ruins, they find half a sphere. The Gullwings travel throughout Spira and encounter many old and new friends, including the three most influential Spirans: Youth League leader Nooj, New Yevon Praetor Baralai, and Gippal, leader of the Machine Faction. Gippal, a ladies' man and an old friend of Rikku's, embarrasses her with a crack about the two of them having "made quite the couple". News spreads about an "awesome sphere" found in Kilika, which draws the attention of both the Youth League and New Yevon. The Gullwings seize the sphere whose footage displays the mysterious man who resembles Tidus standing before a large weapon, mentioning someone named Lenne.
The awesome sphere is returned to either the Youth League or New Yevon, and it is learned from Nooj or Baralai the colossal weapon is called Vegnagun. Leblanc broke into the airship and stole the Gullwings' broken sphere from the Zanarkand Ruins, and in Leblanc's headquarters, Chateau Leblanc, the girls discover Leblanc already had the other half and stole their half to make it whole. After watching the restored sphere it is learned Vegnagun lies hidden underneath Bevelle. Forming a truce with the Leblanc Syndicate, the sphere hunters enter the underground passage under Bevelle formed after the fayth's disappearance and find a secret complex filled with machina.
When the girls reach Vegnagun's lair, they face an antagonistic Bahamut and are forced to fight it. Vegnagun is gone and a large hole is left in its place. Fiends pour out of the temples, and Nooj, Baralai, and Gippal go missing. After defeating a possessed Ixion in Djose Temple, its surprise death blow attack sends Yuna falling down the hole in the former Chamber of the Fayth and into the Farplane. Rikku, Paine, and the others soon hear from her again when she emerges in the Bevelle Underground. Back on the Celsius, Yuna tells everyone about what she learned at the Farplane> Shuyin and Lenne lived during the times of the Machina War a thousand years ago, and Lenne's spirit coalesced into a sphere, which the Gullwings now use as the Songstress dressphere. After learning about Shuyin and Lenne from Maechen after Yuna's 1000 Words concert, Rikku pities Shuyin, as two years ago, she, too, went to great lengths to try and save Yuna from a tragic fate. Now knowing the holes in the temples lead to the Farplane, Yuna plans to talk to Shuyin to tell him how Lenne felt.
Rikku feels that people are always leaving her behind, but Yuna thanks her for "kidnapping" her and letting her join the Gullwings. The girls descend into the depths of the Farplane and defeat Shuyin and Vegnagun. Lenne's spirit puts Shuyin's hatred to rest. The Gullwings leave Spira's leaders at Luca and ride the Celsius to Besaid where Yuna reunites with a revived Tidus.
Despite her dry wit and demeanor, Paine values her friendship with Yuna and Rikku, but it is only after spending three months traveling around Spira by herself that she can express these feelings. Her physical mannerisms are boyish, perhaps a side effect from her past adventures with Nooj, Gippal, and Baralai.
Paine's childhood is unknown, but she grew up during the time of Sin's reign and came to join the Crimson Squad, an elite group of soldiers set up by Yevon. Around the time of Operation Mi'ihen, Paine worked as a recorder for a group of three men: Nooj, Baralai, and Gippal. When the other Crimson Squad members perished in the Den of Woe, Paine's group survived but were put up for execution soon after by Yevon for having witnessed images of the weapon Vegnagun in the cave.
After Operation Mi'ihen, Paine got separated from Gippal, Nooj, and Baralai and searched for them, passing by Yuna while she was sending the dead. Finding each other, the four stayed together for a while, with Paine still recording their travels, while learning how to speak fluent Al Bhed from Gippal. They decided to go their separate ways on the Mi'ihen Highroad, but Nooj betrayed the group by shooting each of them in the back. The Al Bhed came across the fallen Paine, Baralai, and Gippal, and tended to their wounds and kept them out of sight from the temples, thus separating them.
Two years later, Paine joins the sphere hunter group, the Gullwings, to uncover the truth of what happened on that day in the Den of Woe. Whenever any of the other Gullwings asks Paine of her reason for joining she claims it was for the chance to fly on their airship, the Celsius. Shortly after Paine joins the Gullwings, Yuna also joins the group. As the Gullwings go on missions, they are frequently opposed by the Leblanc Syndicate—their rival sphere hunters, led by Leblanc.
Leblanc steals Yuna's Garment Grid to impersonate her and perform a concert in Luca. While the real Yuna dons a moogle costume as a disguise to keep a low profile, Paine and Rikku infiltrate the concert to capture the "impostor Yuna". Rikku and Paine confront Leblanc and chase her out to the docks until being confronted by her two chief henchmen, Logos and Ormi. Yuna joins the fray and reclaims her Garment Grid and begins dancing uncontrollably as though against her will.
With the mission completed, the Gullwings return to the Celsius and continue sphere-hunting until they steal an "Awesome Sphere" from Kilika that records a mysterious machina and an unknown man mentioning someone named Lenne. Upon returning the sphere to either the Youth League or New Yevon, it is learned from Nooj or Baralai that the colossal machina is called Vegnagun. They discover the Leblanc Syndicate had stolen the half-sphere the Gullwings found in the Zanarkand Ruins, forcing them to infiltrate Chateau Leblanc in Guadosalam to reclaim it. To do so, they track down Leblanc Syndicate groups around Spira and steal their uniforms.
During their tracking, they come across the Machine Faction and its leader Gippal, but Paine acts as if they have never met before, confusing him. After obtaining enough uniforms, the Gullwings infiltrate Leblanc's headquarters and find one of Paine's Crimson Spheres that details the events leading up to, during, and after the incident with the Crimson Squad. Paine remains silent about its significance. YRP discover Leblanc already had the other half of the broken sphere and stole their half to make it whole.
After watching the restored sphere, they learn Vegnagun hides underneath Bevelle. Paine is unsurprised that Bevelle "still has its fondness for secrets". Realizing they are on the same side, the Gullwings and the Leblanc Syndicate form a truce. Together they infiltrate Bevelle and enter the underground passage formed after the fayth's disappearance. They fight their way past Baralai to an empty room where the sphere had shown Vegnagun. Instead of finding Vegnagun, the group fights the Dark Aeon Bahamut, and there is a large hole left in Vegnagun's place.
Returning from the venture, the Gullwings learn that Nooj, Gippal, and Baralai have disappeared. Fiends and Dark Aeons emerge in the Besaid, Kilika, and Djose Temples, and when on a mission to purge them all, Yuna falls through the hole in Djose Temple's Chamber of the Fayth. She plummets into the Farplane, where Nooj and Gippal bequeath her two more Crimson Spheres, telling her to give them to Paine. Back on the Celsius, Yuna tells everyone about her encounter with Shuyin while on the Farplane, learning that Lenne wore the Songstress dressphere over a thousand years ago.
Only when pressed on the deck of the Celsius does Paine reveal a little of her past with Nooj, Gippal, Baralai, and the Crimson Squad, telling Yuna how the four of them dreamed about having an airship, traveling Spira. Later, she assists with finding Tobli to set up Yuna's concert in the Thunder Plains, as a way to calm the tensions rising between the Youth League and New Yevon. During the concert, Lenne's spirit appears, and it is revealed she and Shuyin were lovers who were gunned down by Bevelle soldiers after she stopped him from activating Vegnagun. Lenne was a famous songstress and summoner from Zanarkand, who was called to the front lines during the Machina War and Shuyin tried to use Vegnagun to save her. The Gullwings receive another Crimson Sphere, this time from Leblanc herself.
With the final Crimson Sphere obtained, Paine, Rikku, and Yuna enter the Den of Woe and discover the truth behind the events two years ago involving Paine's team. Den of Woe is the place where Shuyin's spirit lingered for a thousand years, and his painful memories and anguish imprinted on the abundance of pyreflies in the den. When the Crimson Squad entered the cave, the pyreflies possessed them driving the squad members to kill one another. Shuyin escaped the den by possessing Nooj, which was why he shot his comrades in the back, severing their friendship. Emerging from the cave with renewed purpose, Paine is determined to free her friends of Shuyin's influence. Realizing that during their meeting under Bevelle with Baralai and Nooj, Shuyin's spirit left Nooj's body to possess Baralai, Paine asks the Gullwings to help her face Baralai and defeat Shuyin. Now knowing the holes in the temples lead to the Farplane, Yuna plans to tell Shuyin how Lenne felt before they died to calm his spirit.
The Gullwings and Leblanc Syndicate enter the Farplane and, with help from Nooj and Gippal, defeat Vegnagun and Shuyin in a joint effort. Lenne emerges from Yuna's Songstress dressphere to console Shuyin, convincing him to rest in peace before they return to the Farplane together. The Gullwings drop Nooj, Baralai, and Gippal at Luca but leave to return Yuna home to Besaid. When Rikku worries about missing a big party back at Luca, Paine says they party enough on their own. Paine later joins Rikku in watching Yuna and Tidus reunite with each other.