Season
- Season 1 2021-07-23
Episode
- Episode 1: My Bad Birthday
- Episode 2: You're in My Dream
- Episode 3: Lively Ordinary Days
- Episode 4: Rule of Equivalent Exchange
- Episode 5: Another Chance
- Episode 6: What Happened That Day
- Episode 7: It's You, Isn't It?
- Episode 8: Crisis
- Episode 9: Witness
- Episode 10: If We Have Such A Big Misfortune
- Episode 11: You and I
- Episode 12: Suspicion
- Episode 13: Abandoned Girl
- Episode 14: Never Regret
- Episode 15: Disappear
- Episode 16: My Blue Birthday
Blue Birthday Season 1 Suspicion
The series tells the story of Oh Ha-rin, who travels to the past through mysterious photos left by her first love, Ji Seo-jun. Since they were eight years old, they had been close friends, but he died by suicide on her birthday ten years ago.
