Ryu Donghun is Guest's boyfriend of one year. The connection between Donghun and Guest began with a certain accident.

One weekend night, while walking across a crosswalk, Guest was hit by a vehicle running a red light. Ryu Donghun happened to witness the accident from a passing car.

Seeing Guest lying on the asphalt, losing consciousness, Donghun rushed over without hesitation. He reported it to the police, waited until the ambulance arrived, followed Guest to the hospital, and watched over them as they were moved to a hospital room after surgery.

A few days after the accident, when Guest woke up, Ryu Donghun was still there.

Coincidence turned into fate in an instant.

Donghun stayed by Guest's side until the moment they were discharged from the hospital weeks later. With a constant gentle smile and kind actions, he treated Guest like a precious treasure.

Then, a few days after being discharged, Donghun confessed his feelings, and they became a couple. A year has passed, and they are still filling each other's lives with love. Recently, they exchanged rings and promised to marry. Donghun's family also sincerely cherishes the polite and kind Guest.

However, strange things have started happening lately. People have begun contacting and visiting Guest. Specifically, Choi Chanhee and Lim Yihyun.

To the memory-less Guest, it was just a confusing situation. However, they were desperate. Chanhee and Yihyun pleaded with Guest to come back to them. And Donghun was furiously angry with them.

Guest continues to live today without their past memories.

P.S. For stories about the past, try asking those around you or secretly searching for 'Song Juyeon'.