The show opens with a peek into the world of Cheum Museum’s curator SUNG DEOK-MI (Park Min-young) as she preps for an exhibition with her team, meticulously working on everything from examining the artworks to setting them up. As soon as her job is done she changes her attire and clutches a huge camera, hurrying over to a throng of fangirls. The fans explode into screams at the arrival of popular idol group White Ocean, and we learn that Deok-mi is a dedicated fan site administrator of the group’s vocalist CHA SI-AN (One), who is also a connoisseur of art.
In New York, suave gallery director RYAN GOLD (Kim Jae-wook) attends an exhibition. His reputation is that he can make or break an artist’s career with a single glance. When a fan asks him when he’s going to work as an artist again, we learn that Ryan started his career as a painter, but hasn’t been able to paint for a few years. His therapist has diagnosed him with Stendahl Syndrome, a condition which causes extreme distress in people upon viewing a beautiful object.
Deok-mi’s mom gets suspicious when she mentions an upcoming business trip and asks if she is still chasing idols around. We find out that after breaking her arm at a fan event when she was 20, Deok-mi had had to give up on her dreams of going abroad to become an artist. Flashbacks of her teenage years reveal that she’s been a fangirl all her life, obsessing over every group from g.o.d to TVXQ. To stop her mom from visiting her house which is basically a shrine to her idol, Deok-mi asks her childhood friend NAM EUN-GI (Ahn Bo-hyun) to deliver mom’s dishes to her. A life-sized cut-out of Cha Si-an surprises Eun-gi at the door and he destroys it, leading Deok-mi to hilariously hurl murder accusations at him.
At an auction in Shanghai, Deok-mi buys art for Cheum’s upcoming exhibition when Ryan walks in and sits beside her. She notes that he looks like Si-an and stares a little too long, prompting him to ask if, along with the artworks, she would like to buy him too. A painting that Deok-mi plans to gift to Si -an opens for bidding and she and Ryan fight to outbid each other. Ryan ends up taking the painting, and when Deok-mi proposes he sells it to her, he flat out refuses.
Upon returning to Korea, Deok-mi is greeted by a convoy of cars outside the gallery. She’s shocked when a team of prosecutors take her in for interrogation because her boss, Director EOM (Kim Sun-young) is involved in an embezzlement case. Later that night, Deok-mi’s best friend LEE SEON-JOO (Park Jin-joo) comes over for a sleepover and to comfort her with soju.
Deok-mi receives a lucrative job offer the next day, with flexible timings that will allow her more time to fangirl. She decides to take the job and leaves her current workplace but Director Eom surprises her by announcing plans to promote her as the new director. Actual fireworks go off in Deok-mi’s head as she imagines ordering an exhibition of Si-an’s photos as the gallery director.
While waiting for Si-an’s arrival at the airport, a bunch of fans check out another popular fan site’s—operated by CINDY (Kim Bo-ra)—invasive pictures of the singer and remark on Cindy’s sasaeng behavior (stalking). Deok-mi arrives in her usual black garb with her face covered and notices right away that Si An’s bodyguards are planning to take an alternate route. Sure enough, Si-an exits from a less-crowded gate, followed by Ryan who was on the same flight. As fans catch on and rush towards the star, a startled Ryan bumps into Deok-mi and they both fall. She yells at him for almost destroying her camera but sprints away before he can unmask her, dropping her diary in the process.
Deok-mi is heartbroken to find out that Director Eom appointed someone else as the new director of the art gallery after promising her the job. Seon-joo takes her dejected friend on a “pilgrimage” which is a kind of fan tour that involves visiting places your idol has gone to. The friends plan to rent the suite Si-an had once stayed in, but find out that someone else—Ryan—has just booked it. Seon-joo approaches him to swap rooms, telling him that she’s in a relationship with someone she can’t easily meet and needs the suite.
Ryan sees Seon-joo and Deok-mi at the bar and assumes that the two are dating courtesy of Seon-joo’s cryptic statement about her forbidden and difficult relationship. He scolds himself for being prejudiced by assuming that Seon-joo was referring to a male lover by default and gives her the key to the suite. Overjoyed, the girls spend a fun night taking pictures in the same spots Si-an had clicked pictures in. The next day, Ryan turns up at the gallery, surprising Deok-mi to the extent that she falls off her ladder at the sight of him.