[2] Directed by Park Dan-hee and co-written by Goo So-yeon and Moon Won-young, the series stars Kim Ye-rim as Oh Ha-rin and Yang Hong-seok as Ji Seo-jun.

The series is a fantasy romance thriller drama in which the female protagonist, Oh Ha-rin, revisits the past through mysterious photos left by her first love, who died on her birthday 10 years ago.

The series tells the story of Oh Ha-rin (Kim Ye-rim), who travels to the past through mysterious photos left by her first love, Ji Seo-joon (Yang Hong-seok).

The series opens with Oh Ha-rin witnessing her best friend and first love, Ji Seo-joon, lying dead in a pool of blood in the photography studio of their school on her 18th birthday.

A confused Ha-rin goes to her birthday party organized by her friends and leaves after one of them, Kim Ui-young, mentions the unexpected and mysterious suicide of Seo-joon.

Soo-jin was suffering from constipation and went home by asking for a lift from a delivery person of a Chinese eatery, but could not remember the name.

Seo-joon and Ha-rin then find another camera whose contents reveal that Hye-min is the real killer, and that she disguised herself as Soo-jin to murder Shin-woo.

[12] Following news reported the script reading was held in Seoul on April 5, 2021,[5] and Ye-rim and Hong-seok were confirmed as the protagonists of the series.

In China, it ranked 7th as the most popular video among all Korean content on streaming sites, and a kind of open chat room was operated to share pictures of the main characters and talk about the drama in real time.

Apart from this, the global OTT platform Viki, which is being serviced in the America, Europe, and Oceania, contains 'Best reversal and suspense!

[27] A Japanese television series of the same title, starring Shion Tsurubo and Airi Matsui, aired on Kansai Telecasting Corporation starting February 8, 2023.