Sungmin is unnoticed most of the time being shy and not very outgoing. On the other hand, Yesung is popular amongst his peers and fellow workers for his ambitious nature and kind attitude. Sungmin is hired at the local library since he was in need of money, and he meets Yesung the manager in training. Sungmin is attracted to this bright light, and unknowingly becomes Yesung's shadow loving everything about the older.

Not noticing the feelings for him, Yesung and Min become friends. Together they go through a series of events, will it end well for shy shadow-like Sungmin and his bright sun Yesung?