An elegant lady (Ga-in Han) suddenly appears at the doorsteps of Seung-min’s (Tae-woong Uhm) architectural firm, asks him to design and rebuild her house on Jeju Island. This reminds Seung-min how the younger him (Je-hoon Lee) met Seo-yeun (Su Ji Bae) in an ‘Introduction to Architecture’ class, and went through a painful yet beautiful first love 15 years ago…… As Seung-min’s old memories of love and heartbreak resurface, can he seize the second chance to re-establish the relationship with his long-lost crush?