When the Phone Rings — Season 1

After receiving a call from Hong Hee-joo's kidnapper, Paik Sa-eon attempts to learn more about him — only to find it's hard to escape his surveillance.

Sa-eon works quickly to track down the caller, forcing Hee-joo to stay hypervigilant. Despite her fears, she continues to play along with the ruse.

After Sa-eon experiences an attack, he grows wary of Hee-joo's relationship with her friend. Meanwhile, an ominous figure makes his presence known.

After receiving the ominous call, Hee-joo abandons her clandestine plan. She then undergoes a tough interview with Sa-eon — sharing an intimate moment.

Sa-eon grapples with feelings of betrayal after learning the truth about Hee-joo. However, when she receives good news, they begin to grow fonder.

Hee-joo confronts a figure from her past who wishes to reveal what she knows. She then embarks on a retreat with Sa-eon — who becomes possessive of her.

Sa-eon and Hee-joo's relationship shifts after her harrowing rescue. Determined to catch the kidnapper, Sa-eon goes full force — with the help of 406.

As Hee-joo and Sa-eon grow closer, the threat from the kidnapper intensifies. Sa-eon discovers an ominous and shocking clue from a past figure.

Hee-joo worries about Sa-eon after learning the truth about him. She later appears on the stage of her dreams, side by side with her love.

While attempting to rescue Hee-joo, Sa-eon discovers another surprising conspirator — whom he later tries to persuade to help locate the kidnapper.

After Hee-joo's bold move, her fate and that of her kidnapper remain uncertain. But Sa-eon refuses to give up — leaving no stone unturned to find her.

Sa-eon abandons everything he's worked for, leaving Hee-joo completely alone. But after a clue arrives, she embarks on a journey to reunite with him.