In 1995, the band Sunset Curve performs a soundcheck at the Orpheum in Los Angeles, where they are set to perform later that night. Just before their big show, Luke, Alex, and Reggie leave to eat "street dogs" while their fourth bandmate, Bobby, stays back to flirt with a waitress named Rose. Tragically, the street dogs turn out to be rancid and the three Sunset Curve members die from food poisoning. Twenty-five years later, teenager Julie Molina is kicked out from her school's music program after a year of being emotionally unable to play music due to her mother's death. While cleaning out her mother's studio, Julie finds and plays a Sunset Curve CD and unintentionally summons the three deceased Sunset Curve members as ghosts. Despite her initial fear, Julie allows them to stay and is inspired by them to make music again, playing a song by her mother on the piano.

After Julie plays the piano and sings for the first time in a year, the ghosts are shocked at her talent and consider asking her to join the band. Julie and her best friend Flynn try to convince the music teacher to let Julie back into the music program, but the teacher refuses, to their dismay. Meanwhile, to help sell their house, Julie's dad, Ray, takes photos of the house and studio, but studio photos depict white orbs; Julie's little brother, Carlos, suspects the orbs may be ghosts. The boys teleport to the beach, where more is learned about the backgrounds of their families. Later, Luke convinces Julie to play a song he wrote in front of the music teacher, but she is reluctant. At her school's Spirit Rally, with encouragement from the guys, Julie gets on stage and begins to perform the song, "Bright", after her archnemesis Carrie and her band Dirty Candy perform. When Julie sings, the band suddenly appears on stage playing their instruments, and they realize that they can be seen by the audience. When the song ends, the band vanishes, leaving everyone to think the boys were holograms.

When the band vanishes, Julie is bombarded with questions. Someone asks her if the band was a hologram and Julie says yes. Julie is then accepted back into the music program by the principal. Flynn then questions Julie, who continues to lie about the band, which makes Flynn upset. After school, Julie lets her dad know that she got back into the music program. In the studio, Alex is panicking about his ghost life, but Luke and Reggie think this is their second chance because, with Julie, they can be the band they never got to be. Overwhelmed, Alex goes for a walk to clear his head and is run over by Willie, a skateboarder who is also a ghost. Willie observes that Alex is new to being a ghost and answers Alex's many questions. Back at the studio, Luke and Reggie find lyrics in Julie's room, which they use to create a song. Julie walks in and they invite her to join the band, but she can't think of anything other than Flynn. She later finds Flynn, about to egg Julie's window for lying to her, and tells her the truth. At first, Flynn doesn't believe her, but the band becomes visible to Flynn once Julie performs "Flying Solo".

The episode opens with Julie and the school singing "I Got the Music", though it is unclear whether it is a dream or not. Willie takes Alex to a closed museum to try and loosen him up. As the boys and Julie collaborate on a new song, Julie tells them about the music of Trevor Wilson which shocks the boys as they discover Trevor is really their former bandmate Bobby, who stole their music and credited it for his own, which has made him rich and famous. Trevor Wilson also is Carrie's father. The boys poof out to haunt Trevor. As part of their revenge against Trevor, the guys ask Willie for help. Willie takes them to the Hollywood Ghost Club to meet Caleb Covington, a ghost with strong powers, and it is revealed that Alex has a crush on Willie.

Caleb Covington introduces Luke, Alex, and Reggie to the Hollywood Ghost Club. The boys are mesmerized by the elaborate musical production numbers. Meanwhile, Flynn DJs at the high school dance where Julie and the Phantoms are to perform later. However, the phantoms soon lose track of time, and Julie is forced to cancel her gig at the dance as a result. As the boys are leaving the club, realizing how late it is, they are given a mysterious stamp by Caleb. When they arrive at the school, Julie, upset with them, confronts them and quits the band. As Julie leaves, the boys suddenly experience a painful jolt, which Reggie compares to how they died 25 years ago.

At Julie's dance class, the boys' lacrosse team coach forces the team to join it to improve their mobility so they can win a game. Nick, Carrie's boyfriend and Julie's crush, and Julie become dance partners. Luke signs up the band for a local talent contest, hoping to get Julie to rejoin the band following the dance. Julie accuses Luke of being selfish, but Alex and Reggie show Julie he isn't by taking her to Luke's parents' house where Luke visits frequently since his death. Julie has a change of heart and helps the boys practice a new song for their performance. However, Julie's father finds that Julie missed three of her classes and a calculus test when she overslept so he grounds her. Julie disobeys her dad and sneaks out of her bedroom to make their performance. After Julie and the Phantoms perform, a talent scout approaches Julie, but as she introduces herself to the band, Julie's father shows up and orders her home.

After Ray reprimands Julie for sneaking out, Julie manages to convince him to allow her to continue performing with the band. Ray feels guilty about interrupting the meeting of the talent scout and the band, so he agrees to throw a party at their house so the band can perform. Luke flirts with Julie under the guise of discussing what song to perform at the party. Nick interrupts them as he is nervous about their dance performance. As Nick and Julie perform their dance number, Julie imagines it is Luke she is dancing with. Alex catches Willie spying on him and confronts him, but Willie leaves abruptly, leaving Alex confused. Later, Julie and the Phantoms perform, which Ray records and uploads to the Internet. Willie decides to come clean and explain that the boys can cheat Caleb's curse and cross over if they complete their "unfinished business", which the boys quickly put together as performing at the Orpheum.

While Alex arrives at the Orpheum, he reminisces about the night he, Luke, and Reggie died. Willie shows up and apologizes to him about introducing them to Caleb. Julie visits Luke's parents to give them a song, which Luke wrote about his mother. Julie hopes that doing so will help Luke. Luke tells Julie that the band has unfinished business that they need to complete before they can cross over or else they will cease to exist. Julie is dismayed at first, but after finding a Sunset Curve T-shirt in her mother's possessions, she realizes the boys are connected to her mother (Rose, the waitress in the first episode, is revealed to be Julie's mother). While Julie is sad she may never see them again, she helps them to come up with a plan to perform at the Orpheum.

Willie helps Julie and the Phantoms become the opening act for Panic! at the Disco at the Orpheum. Carrie watches a video on her computer of Julie and the boys playing which her dad, Trevor, sees and realizes the band is his dead Sunset Curve bandmates. As the boys prepare to join Julie at the Orpheum, Caleb intervenes by transporting them to the Hollywood Ghost Club and forces them to perform with him. As show time approaches, Julie becomes anxious when the guys don't appear. A sign is given to Julie that she is meant to perform and she goes onstage by herself. As she begins performing, the phantoms escape from Caleb and appear and join the performance one by one (Alex, Reggie, then Luke). At the end of the performance, the guys poof out. Julie returns to her studio, and believing that the boys have crossed over, thanks them for being there for her. It is revealed that playing the Orpheum wasn't their unfinished business, and the phantoms never crossed over. Julie begs them to save themselves and join Caleb's band, but they refuse, not wanting to make music without her. Julie and Luke hug, and Luke starts to regain strength. Alex and Reggie then join them, and Caleb's curse is lifted. The next day, Nick comes to Julie's house with flowers, but Caleb appears behind him and possesses him. Julie comes to the door, and greets Nick, unaware that she's actually talking to Caleb.