On March 17, 2026, H1-KEY uploaded a video titled 'What I Really Want To Tell M1-KEY' to their YouTube channel. The video is the music video for the group’s new single, drawing attention for its emotional storyline and striking visuals. It shows the members writing heartfelt letters and delivering them to someone special, deeply moving fans.
In particular, the members’ sincere messages blend with the song to deliver an even bigger emotional punch. This music video once again reminds fans of H1-KEY’s warm, genuine charm. Channel subscribers shared a wide range of reactions, showing strong interest.