Ha-won follows the music that he has memories with Ji-soo, and meets a sound engineer, Seo-woo.

Seo-woo blames herself for interrupting Ha-won, but she is also curious about Ha-won.

While having a hard time after Ji-soo's accident, Seo-woo learns Ha-won's other secret.

Ha-won becomes curious about the Ji-soo device. Meanwhile, In-wook suffers from a severe slump.

Ha-won finds out about Seo-woo's feelings for him. Seo-woo gets a chance to talk to Ji-soo device.

In-wook learns about the number that Ji-soo left, but his unpredictable behavior bothers Soon-ho.