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When we were 18, we first called each other by name. At 21, we fell in love.
In a time when dreams seem out of reach, a teen fencer pursues big ambitions and meets a hardworking young man who seeks to rebuild his life.
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Checked Jul 22, 2026
In a time when dreams seem out of reach, a teen fencer pursues big ambitions and meets a hardworking young man who seeks to rebuild his life.
Cast, crew and production details
Kim Tae-riNa Hee-do
Nam Joo-hyukBaek Yi-jin
BonaKo Yu-rim
Choi Hyun-wookMoon Ji-woong
Lee Ju-myoungJi Seung-wan
Kim Hye-eunYang Chan-mi
Choi Myeong-binKim Min-chae
Joo Bo-youngLee Ye-ji
tvNSouth Korea
Hwa&Dam PicturesSouth Korea
Studio DragonSouth KoreaWatch options above are for the show and may vary by season or episode.
Episode 1
When the IMF financial crisis threatens to slash Na Hee-do's dreams, she sets out to get herself transferred to another school with a fencing program.
Directed by Jung Jee-hyunWritten by Kwon Do-eunGuest stars Park Jin-soo, Jung Yoo-min, Kim Tae-yoo, Lee Ki-bbeum, Song Young-joo, Yu Bee, Jang Yeon-woo, Jung Yong-ju
Where to watch Twenty Five Twenty One
Episode 2
Though taken aback by Ko Yu-rim's cold attitude, Hee-do gives it her best in their first face-off. More of Back Yi-jin's situation comes into focus.
Directed by Jung Jee-hyunWritten by Kwon Do-eunGuest stars Shin Ga-eun, Lim Yong-soon, Kang Hak-soo, Park Bu-keon, Hyeon Jin, Ma Jeong-pil, Moon Woo-bin, Bang Eun-jeong
Where to watch Twenty Five Twenty One
Episode 3
When a fortuitous opportunity presents itself, Hee-do begs her coach for extra training. An unanticipated visitor comes around hoping to see Yi-jin.
Directed by Jung Jee-hyunWritten by Kwon Do-eunGuest stars Moon Woo-bin, Bang Eun-jeong, Jeon Se-yong, You Euna, Seo Young-sam, Seo Jeong-bin, Yeon Seung-bin
Where to watch Twenty Five Twenty One
Episode 4
In exchange for a favor, Hee-do carries out a daily errand for Moon Ji-woong. She happens across a drunk Yi-jin after he fails another job interview.
Directed by Jung Jee-hyunWritten by Kwon Do-eunGuest stars Jung Yong-ju, Moon Woo-bin, Bang Eun-jeong, Ok Joo-ri, Jeon Soo-hwan, Song Jae-saeng, Son Young-soon, Hong Eun-jeong
Where to watch Twenty Five Twenty One
Episode 5
Hee-do takes one giant leap closer to her dream. She's eager to tell Yi-jin the good news — but realizes he's disappeared without a trace.
Directed by Jung Jee-hyunWritten by Kwon Do-eunGuest stars Jung Chung-gu, Seo Jeong-bin, Yeon Seung-bin, Kim Ha-ru, Lee Seon-gu, Lee So-yoon, Kim Na-in, Lee Beom-chan
Where to watch Twenty Five Twenty One
Episode 6
Tensions run high between Hee-do and Yu-rim before an important event. Yi-jin takes on a new assignment, and spots a familiar face in the crowd.
Directed by Jung Jee-hyunWritten by Kwon Do-eunGuest stars Choi Tae-joon, Lee Seon-gu, Lee Dong-kyu, Jung Hyung-suk, Seok-hee, Kim Ji-ho, Song Yo-sep, Jeong Jong-hoon
Where to watch Twenty Five Twenty One
Episode 7
A frustrating media narrative dampens a monumental moment for Hee-do. Yi-jin chases down the only person who may be able to set things right.
Directed by Jung Jee-hyunWritten by Kwon Do-eunGuest stars Baek Suk-kwang, Lee Jung-ok, Ok Ye-rin, Kim Ha-ru, Lee Seon-gu, Lee Dong-kyu, Jung Hyung-suk, Han Gyu-hyuk
Where to watch Twenty Five Twenty One
Episode 8
Hee-do perceives a growing distance between herself and Yi-jin, even as he moves back into the neighborhood. Trouble at home adds to Yu-rim's stress.
Directed by Jung Jee-hyunWritten by Kwon Do-eunGuest stars Ok Joo-ri, Bae Seong-il, Jeon Yeong, Lee Jun-hee, Park Eun-young, Yun Bu-jin, Goo Si-yeon, Kwak Myung-hwa
Where to watch Twenty Five Twenty One
Episode 9
As Yu-rim's perspective on Hee-do shifts, so does her behavior. While Hee-do avoids seeing Yi-jin, he volunteers for a special documentary project.
Directed by Jung Jee-hyunWritten by Kwon Do-eunGuest stars Park Jung-pyo, Jung Hyung-suk, Park Yoon, Cho Min-wook, Yoo Min-joo, Yoon Ju-man, Lee Si-hoo, Park Ji-ho
Where to watch Twenty Five Twenty One
Episode 10
Under the guise of work, Yi-jin takes Hee-do and Yu-rim on a weekend getaway to the ocean — and agrees to let Ji Seung-wan and Ji-woong tag along.
Directed by Jung Jee-hyunWritten by Kwon Do-eunGuest stars Kim Bum-joon, Park Jung-pyo, Jung Hyung-suk, Park Yoon, Cho Min-wook, Yoon Ju-man, Lee Si-hoo, Park Ji-ho
Where to watch Twenty Five Twenty One
Episode 11
Hee-do grows upset when her career-obsessed mother fails to keep a promise. Yi-jin helps out Ji-woong's plans for a grand gesture at a music festival.
Directed by Jung Jee-hyunWritten by Kwon Do-eunGuest stars Baek Suk-kwang, Ok Joo-ri, Ok Ye-rin, Kyung Da-eun, Lee Kyung-oh, Park Jung-pyo, Jung Hyung-suk, Park Yoon
Where to watch Twenty Five Twenty One
Episode 12
Unable to hold back from putting an end to a teacher's abusive behavior, Seung-wan stands her ground. Hee-do and Yu-rim support a distraught teammate.
Directed by Jung Jee-hyunWritten by Kwon Do-eunGuest stars Choi Tae-joon, Kim Bum-joon, Jo Nam-hee, Jung Hyung-suk, Yoon Se-woong, Oh Choong-geun, Kim Tae-moon, Jeong Young-do
Where to watch Twenty Five Twenty One
Episode 13
Warnings about allowing his personal ties to affect his work weigh heavily on Yi-jin. The school fencing team enters their last competition together.
Directed by Jung Jee-hyunWritten by Kwon Do-eunGuest stars Ok Joo-ri, Jung Hyung-suk, Ji Hyun-woo, Kang Sung-hwa, Im Woo-chan, Kang Seong-jin, Baek Ji-hye, Lee Sang-kyung
Where to watch Twenty Five Twenty One
Episode 14
Shouldering the burdens of a sudden misfortune in her family, Yu-rim arrives at a decision that places her in hot water with the public.
Directed by Jung Jee-hyunWritten by Kwon Do-eunGuest stars Ri Min, Yang Eun-sol, Kim Jang-hwan, So Jun-seong, Na Ho-won, Choe Min, Cha Mi-kyeong, Son Dong-soo
Where to watch Twenty Five Twenty One
Episode 15
Hee-do once again finds herself opposite her most formidable opponent. Yi-jin is busier than ever after transferring to another department.
Directed by Jung Jee-hyunWritten by Kwon Do-eunGuest stars Kim Si-kook, Kim Joo-ah, Park Yong, Lee Sung-il, Ha Seung-yeon, Park Ki-deok, Kwon Dan-a
Where to watch Twenty Five Twenty One
Episode 16
In an emotionally charged exchange, Hee-do and Yi-jin confront the state of their relationship. Hee-do accidentally leaves her diary on a bus.
Directed by Jung Jee-hyunWritten by Kwon Do-eunGuest stars Kang Hoon, Jung Chung-gu, Park Ki-deok, Kwon Dan-a, Park Se-in, Kang Moon-kyung, Park Bin, Park Bo-bae
Where to watch Twenty Five Twenty OneEpisode information updated Jul 22, 2026
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