Princess Deok Hye was the last princess of Korea. Under Japanese colonial rule, she is taken to Japan as a hostage. With the era’s harsh conditions, she struggles to maintain the hope of the Korean people. Jang Han is a fighter for Korean independence. His mission is to bring Princess Deok Hye back to South Korea, and he also loves her.
When his boss, Dae Jung, goes missing in a ship accident, the company sends Woo Joo to Osaka to finish his business. On his last day in the city, Woo Joo chases someone looking exactly like Dae Jung to Taisho, an area in Osaka. He ends up losing him, but the sound of a guitar draws Woo Joo to a small bar, Pier 34. Its owner, Snow, somehow reminds him of Dae Jung, and listening to his music brings back memories. After passing out right there, Woo Joo ends up missing his flight back to Korea. He quits his job on a whim and soon meets Haruna, who is learning how to play the guitar from Snow. Woo Joo decides to stay at Pier 34 until he finds Dae Jung and so begins an unlikely vacation for him.
Woo Hyun is a Korean man, and Haruka is a Japanese woman. They live different lives, but they both carry emotional scars from their first love. While looking for answers and hope, their fateful encounter will change their lives. It started with one message… Haruka, a stage actress in Seoul, has been in a slump ever since she broke up with her first love. She cannot forget him and keeps sending messages that go unread on LINE. Despite her emotional hurt, Haruka wants to believe in love. In Tokyo, Woo Hyun, an aspiring movie director, keeps on doing interviews concerning “love”. After being deeply hurt by his girlfriend, who thought about getting married, he no longer believes in love. Haruka and Woo Hyun have both grown timid of love. The two of them, who live apart in Tokyo and Seoul, have a chance encounter because of a LINE message delivered to Woo Hyun’s smartphone from Haruka. They exchange messages without knowing each other’s faces and are drawn to each other before they realise it
Ami, a backpacker from Japan who is four years older than high school student Jimmy, shows up at his part-time job. The two end up spending the summer working at the same store, but Jimmy gradually develops a faint crush on Ami. The two of them grew closer as they rode motorcycles together at night and went to the movies, but suddenly, Ami decided to return to Japan. Ami proposes her "one promise" to Jimmy, who can't sort out his feelings. As time passes, Jimmy visits his parents' house for the first time in a while and finds a postcard that Ami sent him 18 years ago when she returned to Japan. Jimmy's memories of his first love come back to him, and he takes his first solo trip to Japan to confront his past and examine his present. Jimmy rides the train while listening to songs that remind him of his memories with Ami, and he heads to her hometown. Will Jimmy be able to reunite with Ami?
